“The difference between weather and climate is a measure of time. Weather is what conditions of the atmosphere are over a short period of time, and climate is how the atmosphere “behaves” over relatively long periods of time”
“Climate is what you expect – weather is what you get”
Robert Heinlein (via Dame Julia Slingo)
OK, here’s a really simple summary:
Currently, the Sun is in a slight cooling phase. And outside Earth’s greenhouse layer, as expected, we measure slight cooling. But inside the layer, it’s warming faster than the sun would cause even in a warming phase.
The Earth’s core is not heating, so it has to be the gas layer. We don’t yet fully understand the greenhouse effect, but what we do know does predict exactly the effect we observe.
Now. The main greenhouse gas is water vapour. But that’s not changed enough to explain any extra heat. CO2 ‘radiative forcing’ can. And if we calculate how much warming 400 ppm should deliver, we get the temperatures we see. It has to be this seemingly tiny amount of CO2.
But is the CO2 natural? No. The last caldera was 74,000 years ago, the last big meteor was 66 million, and natural weathering is insignificant. It has to be man-made.
And we can now clearly identify the fingerprint of man-made warming around the globe in the increasing frequency and intensity of storms, bush fires, ice / tundra melt, acidification, etc.
Modern Climate Science is today on a par with Evolution and Gravity. We can’t yet explain every detail, but what we do know demands rapid and radical action. If we’re wrong we may have changed the economy slightly, with some minor costs and a lot of major benefits. But if we are right we will have staved off a catastrophe for the human race – and many other species.
A handy list of references on topical debating points can be found here, and see below for more detail on many of the more common ones with links in-line.
Please bear in mind throughout this post that, as Jon Fuller reminds us:
• Every court in the world accepts that climate change is primarily caused by human activities. That is because the science has been proven beyond all reasonable doubt. The anti-science, climate change deniers cannot bring a single case to court because, in the eyes of the law, they lack all credibility.
• When all peer reviewed scientific research on climate change produced in 2013 and 2014 was recently reviewed it was found that of the 24,210 papers (by 69,406 authors) just 5 papers (by 4 authors) disputed that climate change is due to burning fossil fuels and other human activities.
• 99.99% of peer reviewed science shows that the climate change deniers are wrong.
• Every single science university in Europe says the climate change deniers are wrong.
• The Vatican, CofE and every major religion say the climate change deniers are wrong.
• The Pentagon, NATO and other national security agencies in Europe say the climate change deniers are wrong (climate change will cause ever greater international conflict and war).
• The IMF, OECD, World Bank, IEA, World Economic Forum and Bank of England say the climate change deniers are wrong (climate change might bankrupt us all)
• And finally; Remember – China has the death penalty, and China disproves the argument that there is a global conspiracy of scientists. China has hundreds of thousands scientists and science students in universities studying the effect of the various greenhouse gases, and how those gases alter climate. Those scientists have shown the political elite in the Communist Party that the science is real. Consequently that nation is spending hundreds of billions on low carbon technologies, trying to begin the shift away from coal. If any of those scientists were found to have deceived the Communist Party, causing the loss of hundreds of billions of revenue to the state, they would be executed.”
And we can add to China the other 196 countries that signed the Paris Agreement, most major NGOs and a rapidly growing number of businesses and corporations around the world – including even some from the fossil fuel industry.
Not to mention billions of citizens.
Piers Sellars, who agreed to launch the Priestley International Centre for Climate, but was, sadly, not well enough to attend, likened the Earth’s atmosphere to a Thin Blue Ribbon. All the greenhouse gases that are doing all the damage lie in the bottom half of that narrow strip.
Most diagrams designed to show how global warming works are misleading because they suggest a very deep atmosphere, but this is how big the gases around Earth would be if you scraped them all into a ball (the one on the right).
The size of all the water on the left is even more surprising. The fresh water ball is even smaller, see the video below – and the 12 inches of soil upon which all life depends is even smaller. And we’ve been chucking crap, chemicals and plastic into all of it for centuries.
Meanwhile, this is how much carbon-absorbing forest we’ve lost since humans first resorted to slash and burn agriculture. (A 2015 report estimates that the number of trees – not just forest trees – has fallen by approx 46% since the start of human civilization).
And we all know all about the extent of urbanisation and consequent pollution today.
Seen in these terms, it’s much easier to understand how humans could be damaging our seas and atmosphere to a point where they might no longer be capable of supporting civilisation as we know it.
Just in case this concept is new to you (can there still be anyone?) here is a short film which explains how man-made Co2 is rapidly warming the earth (on top of the very slow natural warming and cooling):
And here is the simple ‘proof’ you might be lacking – and by measurement, not modelling.
Let’s go through this together:
ME: All the earth’s heat, (apart from 0.0003%), comes from the sun. Small amounts of water vapour, plus minuscule quantities of carbon dioxide (and even teenier amounts of methane, actually, which is much worse – though it soon breaks down into yet more CO2) in the Earth’s atmosphere trap this heat by reflecting it back to the surface.
YOU: Minuscule amounts of CO2? That doesn’t sound like a problem…
ME: No, but it is. We’ve known about the effect since 1824 and it’s very easily proved. And if we could only see CO2, it would be easier to accept that 400ppm is actually a massive amount.
YOU: But CO2 is not an ‘ideal gas,’ so adding more doesn’t increase heating.
ME: Not of itself, no it doesn’t. But this is not just about the behaviour of molecules within the gas, but how the gas behaves in the atmosphere.
YOU: But CO2 is a good thing – plants die without it.
ME: Yes, the right amount is essential, and not only for plants. Without an atmosphere containing CO2 and other greenhouse gasses, Earth would be a frozen desert. With too much CO2, it would be a hot desert. And by the way – too much CO2 is actually bad for trees.
YOU: But surely the planet has been much hotter and cooler in the past?
ME: It has. The sun’s heat varies very slowly over aeons, either because the Sun is a teeny bit closer or further away (our orbit wobbles), or because it’s a bit hotter or cooler itself, thanks to long and short solar cycles. And both these changes affect the amount of heat reaching Earth.
YOU: So it’s true then. The climate HAS always changed.
ME: Yup, it has, but very, very, VERY slowly. Slow enough for life to adapt by moving to a new location – or even evolving into new species (climate change is likely to have been the primary driver of species diversity).
YOU: Well, if Earth has been hotter in the past, what’s the problem?
ME: Two problems actually. The first is that today’s complex human society evolved in a period of calm, benign climate. So even if we had all the time in the world to adapt, we’d be looking at changes beyond contemplation today. We are too settled. We grow the wrong crops, rely on the wrong medicines. Our cities are in the wrong places. Our technology is wrong. And there are probably too many people for a hotter, more turbulent planet too.
YOU: But we can adapt…
Me: No. We can’t, actually. Because of the second problem; speed of change. Last time anything like this happened it was due to a meteor. Ok, it happened much faster than what’s happening today, but in geological time-frames they both count as very rapid. The meteor wiped out most of life on Earth because only a few species were suited to the new conditions. The rest failed. Actually, this is already happening again today, even with one degree of warming.
YOU: But that’s not only because of the climate, surely?
Me: True. There are various other human-caused factors like pollution, pesticides and deforestation, but the most important is that crops and the lower levels of the food chain (especially pollinators) are highly dependent on weather. Moisture, temperature and the synchronisation of food and prey are critical, especially for new-born young – and that’s going badly out of whack now. Also, while a warmer atmosphere with more CO2 is indeed better for many species in the short term, some are pests that we don’t want more of, especially in places where they have no natural predators. And random weather is good for nobody if crops are flooded or parched. Life on Earth is not at risk, but most current species are.
YOU: But humans are smart – we can change how we produce food.
Me: Not quickly enough. We still rely on ecosystem services which are already suffering. With our fragile and fractious society, we’re the most vulnerable species of all.
YOU: And we know all this for sure?
ME: Yes. The graphs of solar activity, and Earth’s temperature back since mankind evolved match pretty closely. But as the Industrial Revolution got going, the graphs began to diverge.
YOU: Ah – but I’ve seen graphs proving that CO2 actually increases because of natural warming, not the other way around. So your argument is just so much smoke. Ha ha.
ME: Ha ha indeed. But you’re not entirely wrong here. While the basic effects of CO2 are simple and well-understood, the science around it is actually very complex. Sometimes it does indeed increase as a result of solar warming, because hotter oceans release more CO2. But other times, as now, it causes heating by trapping radiation. (And this makes things even worse, of course, as the oceans then release even more CO2). Actually there’s quite a lot about CO2 that still puzzles scientists, but almost everyone is satisfied that we understand enough now to trigger drastic action.
YOU: But if you’re not 100% sure, then surely it’s irresponsible to act. You might be completely wrong.
ME: Yes, that’s possible, but the more we find out the more confident we are that it’s really happening.
YOU: But you don’t know everything…
ME: No, but let’s take an analogy; cancer treatment. Science is really getting a grip on this today, thankfully, but we still don’t understand everything. Never-the-less, medics have been treating cancer with increasing success for centuries. Should they have done nothing at all until they knew every single thing there was to know about cancer? Or do what they can, and learn as they went?
ME: Or say a pilot is taking the great circle route from Oslo to Vancouver when a warning light suggests the plane might be going to crash into the Arctic Ocean. But she can’t be 100% sure. Does she fly on in hope, or turn back to the nearest airport?
YOU: I see your point.
ME: Look. Science is never finished, it’s always developing – so by definition it’s always wrong. But sometimes it tells us enough to justify action. Like saying; this rocket will take you to the moon and back – jump in and give it a go. Or this plant will feed more people, grow some. Or this virus is going to infect 80% of the people on Earth – better take these measures now.
YOU: Touché. But climate science is so very, very complicated.
ME: It is. But we do have one ‘smoking gun’: The sun’s actually getting a teeny bit cooler at the moment, yet Earth’s surface is still warming.
YOU: How can that be?
ME: Well, the outside of the atmosphere is loosing more heat than usual, exactly as we’d expect it to whenever the sun dims. So we know that the heating must be happening inside it somehow. But the Earth’s core is not warming, and our physical heating activities are nothing like sufficient to explain the anomaly. We’ve ruled out meteors, volcanos, cosmic rays, polar flips and so on, so it must be the atmosphere itself that’s somehow trapping more of the sun’s heat.
YOU: Ah. You mentioned water vapour at the top. I’ve heard that’s the real cause…
ME: Yes it’s a major greenhouse gas – with much more impact within the normal system than CO2. But the quantity of water vapour hasn’t changed. So it’s very unlikely to be the cause of increased warming.
YOU: So that leaves only one likely culprit; CO2?
ME: Yes. CO2 enters the system naturally, either very slowly due to the weathering of rock, or very rapidly due to volcanic eruptions or large meteor strikes.
YOU: There you are then: Natural.
ME: No. The heat gain is much much too great to be explained by natural weathering. (Actually, weathering can reduce greenhouse gas).
YOU: But you said volcanoes and meteors too…
ME: There have been no eruptions or meteor strikes anything like big enough during this period to explain the warming.
YOU: Well, what about cosmic rays and/or polar flips then?
ME: Not cosmic rays, that’s clear, or polar reversal because while we do think it’s a factor, we know there was no change in glacial extent last time it happened – when the magnetic field became very weak. So we can’t blame either. But do know we’ve been been pulling carbon out of the ground, burning it, and releasing it into the atmosphere for about 150 years – since around the point when predicted and actual temperatures began to diverge…
YOU: Hmm. So when you calculate what a couple of centuries of man-made CO2 would do to the temperature, how well does it match up?
ME: Pretty well. There’s still a lot we don’t understand, and there are still a few anomalies, but it’s a very convincing case – which is why so many nations, companies, organisations and people in the street are demanding that we decarbonise now, hard and fast.
YOU: They say we have about a decade to halve emissions if we are to avoid a catastrophe. Is that true?
Me: Catastrophe is a strong word but don’t know how else you describe the loss of billions of lives, squillions of species and the collapse of society as we know it.
YOU: But isn’t this all founded on computer models – and we can’t make major decisions based on them, can we?
ME: What else can we do? The basic science is telling us there’s a major problem. And models are the only tool we have to try to find out how bad it might get – under different possible scenarios.
YOU: But that’s just expensive guessing..
ME: No – it’s highly specialised science, which is becoming ever more reliable.
YOU: How can you tell?
ME: Hindcasting. You set up your model to describe the current situation, then run it backwards to see how well it matches the measured, historic data. It fits, so then you run it forwards and see where it takes you. It might be wrong, but the broader scientific community are confident that the new breed of climate models are reliable (the one in our department was used to develop the recent 1.5 degree proposals). More importantly, models are currently the only tool we have, so we have to use them. And in the absence of any other evidence or prediction, given that they advise radical action, we have to respond.
ME: Ok, if you’re not convinced, please watch this:
So how is this panning out today? Well, some people call this film below ‘alarmism’ – or even ‘warmism’:
If you think that’s ‘hysterical’ by both meanings of the word, and are not convinced that climate change (the direct consequence of global warming – both terms having been used since the phenomenon was first observed, as we saw above) is happening, that it’s serious, and that humans are largely to blame, may I humbly suggest that you ask yourself these four questions, which I’ve had to ask myself:
1) Do I really know enough about climate science to make an informed judgement?
There are effectively only two levels at which you can engage with climate science, the fairly superficial – as per this blog, and a proper full understanding of the whole shebang (which ‘proper’ climate scientists have).
Dipping in anywhere in between is risky – you can think you know what you’re talking about but be hopelessly wrong, because there’s a whole area of relevant science you’re not taking into account.
Because, although simple in principle, this is a highly specialised discipline; an ‘A’ level or even an MSc in chemistry or physics may not be enough.
If you really think you know enough, then I’d love to hear your hypotheses, theories and evidence, so they can be tested – as all science should be. There are always minority views which eventually prove to be game-changers, but they do have to stand up to expert investigation, and until they do, science treats them with caution. (Would you like to be treated for a fractured skull with a homeopathic remedy?) So far most maverick theories in this field simply have not panned out as reliable, but the scientists’ door is always open.
If, however, the answer to the question above is ‘no’ then, like me, you will have to decide who to trust. So the next question has to be:
2) Who provided the evidence that convinced me?
Where did their evidence originate, and how reliable was it? Did it come from a qualified team whose work was tested by qualified peers, or did it come from semi-qualified ‘experts’ or, worse, from unqualified people perhaps with a political axe to grind?
If the former, fair enough – contrary to popular opinion, good scientists are (mostly) alert to new ideas, and would be delighted to be proved wrong in this case. They really would – believe me. But if the latter, then the third question has to be:
3) Did I simply choose, or accept, the theory which made most sense to me?
If so, this would have been entirely reasonable – it’s what all sensible people do – but it doesn’t follow that your ‘logical’ theory is in fact correct. Counter-intuitive science often proves to be reliable – as in heavier-than-air flight. Or the earth going round the sun. Or even evolution – in fact pretty much everything we found out using science not storytelling. Each was discovered thanks to someone getting curious, doing some experiments and, crucially, waiting until there was enough evidence pointing in the same direction before starting to decide what they might be looking at.
This article explains beautifully:
“Science always has to ask open-ended questions, because science is not a method for trying to prove something. Rather, science is a method for trying to learn what is true. It is a method for setting aside your biases, testing possibilities, and discerning objective reality. Thus, science must always go from evidence to a conclusion. It can never go from a conclusion to evidence. Indeed, if you start with a conclusion, then look for evidence to support that conclusion, you are, by definition, doing pseudoscience. This fraudulent strategy of trying to prove a belief while operating under the guise of science is extremely common among science deniers.“
And people do that because they have already decided on a theory they find comfortable. So finally maybe you need to ask yourself:
4) Do I need to challenge my ‘personal paradigm’ (see below) – step away from my comfort zone and try to assess the evidence before me as a scientist would; dispassionately and honestly (as, eventually, these scientists, meteorologists and political commentators did)?
If you think you know something that mainstream science does not, or if you favour the views of maverick scientists who mainstream scientists question, first of all; beware the Galileo Gambit. This can be paraphrased as:
They laughed at Galileo, and he was right. They laugh at me, therefore I am right.
People who use this gambit are usually accusing climate scientists of ‘group-think’ – the evil twin of consensus, about which more below. The longer definition goes: Because Galileo railed a lone voice against the consensus view, and was proved to be correct, we should champion lone voices over majority opinion. This is plainly stupid. If taken seriously, we’d have to champion the likes of Andrew Wakefield, David Ike and other dangerous Pseudoscientists as well as a wide range of ‘inspirational’ non-scientists, of whom there are a worryingly large number.
More importantly, Galileo was defended, and eventually vindicated, by scientists against a non-scientific consensus: namely The Catholic Church.
Galileo did use a method, but it was Descartes who is credited with initiating what eventually developed into the Scientific Method by the 19th or even 20th century. One of its many purposes was to discourage group-think – and it does this very well. The whole idea is to find fault with each other’s theories – and it is this ‘productive rivalry’ that drives scientists careers. And their salaries.
Here’s a useful thought from a very similar debate:
If scientists agree, it tends to mean that the argument has been won – for the time being, at least. Though of course there are lots of areas where strong disagreement abides, or where minority views later prove to be correct, or where something new overturns all previous opinion. That’s good and healthy – but if you need to act on science, it makes sense to at least start with the majority view – that’s the one the courts are most likely to judge you on if things go wrong!
Remember that while it’s tempting to back the little guy just because he’s the little guy, (we instinctively back the David against Goliath,) the little guy might not be properly qualified. Even if well-meaning he may be ignorant of key factors, or a victim of selection bias, or even survivorship bias.
If you want to understand climate science properly, please follow the links in the text or here. They challenge the more common maverick views that I list in the next section.
Google will find you many other sites which support the mainstream or ‘consensus’ view – as well as some initially very convincing sites which say differently. Please treat these with extreme caution. (A lot of graphs and technical terms are no guarantee of authenticity).
The maverick sites are a product of the free-for-all that the internet now provides. Some are backed by publications, but none by peer review journals, so it’s something of a tragedy for humanity that it’s often the maverick sites, rather than reputable journals, which are referenced by journalists from – especially – the Mail, the Express and the Telegraph in the UK, and many other ‘libertarian-minded’ media outlets around the world. Sometimes this is because their proprietors have some agenda, and sometime it’s just because they’ll get more readers this way. Why, I’m not sure. Maybe they just tell a better story – but we’ll need to get to my second blog before we explore that one.
Meanwhile, remember; science does not care about your politics. It just is.
The sites I’ve linked to below are run by and/or monitored by professional scientists whose views are informed by sophisticated (and cross-verified) models, verified data, and peer reviewed opinion. Most of the others – including a terrifying slew of YouTube and similar sites – are run by people who do not do their own field research or publish in reputable journals, but have just enough expertise to appear to find technical fault with the mainstream view, for one reason or another – and it’s usually politics, if we are honest.
This, below, will probably have had a lot to do with it: Many people just don’t understand what the scientists are saying, and think, for example, that they are admitting to being biased (bias), or fraud when they are simply referring to the processing of data (as in ‘manipulating’):
Examined in any depth, these criticisms are usually based on what are now old chestnuts – misunderstandings or mischief which has long since been corrected by authoritative explanations (see, again, below). But it can be tricky for the lay visitor to untangle the rights and wrongs, facts, faiths and fantasies of these arguments – not least because the maverick nay-sayers always challenge every correction – and usually vehemently, and come up with impressive-sounding ‘experts’ to back their views.
Equally confusingly, proper scientists nuance their opinions, and typically use technical jargon supported by complex graphics. Maverick sites seemingly display just as impressive language and graphics as the mainstream ones, but, tellingly, they seldom display properly nuanced opinions, while frequently intermingle ideological rhetoric with their science. (Yes, I do this a bit here, but I’m not a scientist, and I’m not asking you to trust me. I’m asking you to go read the reliable science and trust that).
Each ‘side’ claims the other is doctoring the data, so you need always to follow rebuttal and counter-rebuttal, back and back, until you encounter something which is clearly reliable – i.e peer-reviewed by people who fully understand and can evaluate and replicate the experiments, and then published in an authoritative journal (not a politically-motivated blog or YouTube) – as you always will if you look hard enough.
There are those who say the peer-review process itself is flawed, but what else do we have? Religious faith? Pig ignorance? Google?
No. If you find yourself dismissing mainstream science out of hand, then you need to go somewhere quiet and have a good long think. Or go and actually meet a few climate scientists. You’ll soon see that they are genuine and very very worried people.
Society simply has to go with the best-informed opinions we have, in a spirit of productive debate – and perhaps with a bit of common sense. If that’s ok with you, please read on.
Some people fervently believe that climate science is like a balloon that can be popped by one error, disproven theory or damaged dataset. Not so. It’s actually more like a bramble thicket; rooted in the soil of basic physics, constantly growing and branching, and composed of tough, thorny, intersecting theories which all support each other. (This is called ‘concilience‘ in the trade).
You can cut out a great many stems without materially changing the thicket. But it will surely pop any maverick hot-air balloon which drifts into contact!
Meanwhile, many on the majority side love to claim that climate science is ‘settled.’ I never do because this implies that all the theories are fully proven – which they are decidedly not – though I think we can say, post Paris, that the debate is, finally, settled.
Climate science is actually relatively new. The basic principles have been known for centuries, but the discipline did not get going in earnest until 1984, when Farman, Gardiner and Shanklin discovered the hole in the Ozone layer and everyone started cramming on their thinking hats.
Like all science, it does and will evolve, but this is not evidence of incompetence or corruption: The evolution of ideas and theory is actually healthy and necessary. (Think of the advance of medicine – and how confident we are today when we slice open a patient).
It would be fantastic if new, robust discoveries could somehow let us off the climate hook, but, sadly, nearly all recent data has tended the other, more scary way:
And if you’d like to keep up to speed with the latest developments presented, usually, in layman’s terms and think you can deal with relentless bad news, just follow Climate Geek, (of which I am one of the admins).
Truth, Lies and Websites
In spite of the above, I am myself not professionally qualified to judge the veracity of the ‘majority view’ websites below. I have done my best to be critical, but this blog can only be my personal opinion – restricted, for sure, by my own paradigm. I will, however, gladly do my best to explain my opinion if you ask (hey – you may even change my mind!) – and I can report that climate experts who I know personally ‘tend to’ agree with me – and that caveat is the typical caution of thoroughly professional boffins!
So here are the websites I ‘largely’ trust.
RealClimate (with a comprehensive list of reliable websites)
New Scientist Guide for the Perplexed
Climate Geek (our Facebook page for regular news and comment)
Cimate Disinformation Database
Class Central (full course of videos on the science and social impact)
For balance, you can explore the maverick views on WattsUpWithThat – but please be aware that no climate scientist I know would give (almost) anything there any credence – see here and here.
*The term skeptical, applied to science, really just means ‘thorough’ because all good scientists are always sceptical of both their own and others’ work. So Climate ‘Skeptics’ might be better termed ‘Contrarians’ if they hold an evidence-based minority view, or ‘Deniers’ if they flatly refuse to accept mainstream science because they don’t like the implications. I avoid the latter term because it has unfortunate connotations, and favour ‘Maverick’ or ‘Minority’ here. And if you stumble upon a load of very professional-seeming polemic which rubbishes John Cook and Skeptical Science, please look deeper into their arguments. It’s all mouth and no plus fours.
Here are some of the common objections to the mainstream expert view. There are scores more which you’ll find on the maverick links, very few of them even slightly convincing – to me, anyway:
MYTH: “There’s been no warming since 1998.“ This is akin to seeing a wave falling back down a beach and concluding that the tide is therefore not rising. Also, the readings which suggested no surface warming, as measured by satellites (whose data is generally considered to be none too robust) on which this view was based, take no account of deep water heating. New evidence suggests major heat (denser water / more energy / heat) has been building up in the ocean depths throughout this period. 2015 was the hottest since records began, and the years since have been increasingly chaotic and alarmingly warm. More
MYTH: “The climate has always changed.“ Yes it has, but much much much much much much (is that enough muches?) slower than we’ve seen in the last 150 years. These changes were mostly due to long slow solar cycles, which can’t explain current warming. More
MYTH: “It’s Volcanoes.” According to the US Geological Survey, human activity produces as much CO2 in a few days as all the Earth’s volcanoes produce in a year. Also annual human production of CO2 is roughly the same as one or two supervolcanoes. The last supervolcano eruption was about 70,000 years ago, and the only other thing big enough to cause climate change, an asteriod strike, has not happened for more than 66 million years, so it’s not that either. (Natural weathering of rock is way too tiny to be a factor).
MYTH: “It’s the sun.” No it’s not – we can track solar activity and wobbles in the earth’s distance from it (which are the two main variants) and the climate on Earth back many thousands of years, and the graphs match pretty well – until the Industrial Revolution, when they begin to diverge strongly. The sun is actually in a very slightly cooler phase at the moment, and the upper troposphere (beyond the greenhouse gases) is, as we’d expect, cooling. Yet inside the ‘greenhouse’, the temperature is rising. More
Here is a beautifully animated graph which explains all the ‘forcings’ very nicely indeed.
MYTH: “CO2 is not a pollutant.” In this case it is. Just as the definition of a weed is a plant in the wrong place, so the definition of a pollutant is a chemical (or noise, or light or anything), in the wrong place. And though we do need a balanced amount of CO2 for plants to grow, too much is certainly pollution. More
MYTH: “The Ideal Gas Law means that more CO2 cannot deliver more warming.” The Ideal Gas Law cannot explain the observable temperature profile of the troposphere. You also need to employ the laws of thermodynamics, the universal theory of gravitation, and the assumption that convection is the main form of heat transfer within the troposphere. While it’s fair to say “there’s no more capacity in CO2’s absorption spectrum” it’s very wrong to infer that additional CO2 has no impact. This is a common misunderstanding of how the greenhouse effect functions. If the atmosphere really was just absorbing all the infra-red (IR) radiation from the Earth, it would have roasted us all long ago. This doesn’t happen because as well as absorbing IR the air also emits it. So adding more CO2 reduces the rate of heat being emitted from the atmosphere to space. At the surface, the air is dense and most of the IR is absorbed, then emitted, reabsorbed, emitted, reabsorbed – up and up the air column. Eventually the air gets so thin that there isn’t much CO2 (or anything else) to absorb the IR, and the heat finally escapes to space. Adding more CO2 increases the density of CO2, and critically increases the altitude at which the density is low enough for IR to escape to space. As this altitude of escape increases, it cools, thus reducing the flow of energy to space. As such, the concept of saturation doesn’t really exist.
MYTH: “CO2 is a only trace element – at 400ppm it can’t be causing a problem.” A very reasonable assumption. But wrong. More. And here is a very good 24 minute lecture by Richard Alley if you want chapter and verse (and do check out his others on youtube too).
MYTH: “CO2 rise follows temperature rise, rather than causing it.” Yes, in the past this has happened, but now there’s so much CO2 in the system it is actually trapping heat – it’s all to do with how the oceans absorb gas. Last time there was this much CO2 it was indeed caused by warming, but very very slow warming, ‘forced’ by very very long solar cycles – which can’t explain the CO2 up there now. More
MYTH: “Manmade emissions are dwarfed by natural emissions.” True, but natural CO2 is reabsorbed by planetary cycles at the same rate it’s released, so is not increasing overall. The only change is the arrival of man-made CO2, which plants and the sea can’t absorb fast enough. (And meanwhile, sea life is also in additional trouble because of the build up in carbonic acid). More
MYTH: “CO2 is good for plants, and animals can adapt.” Not in the time available they can’t. Very small changes in temperature and moisture can have huge effects on microbes, soils, roots, pollinators, pests and diseases. Our ecosystem services (oxygen, clean water, plants etc.) are vulnerable, and the consequences are severe for bugs, crops – and therefore us. More
MYTH: “It’s water vapour” Nope
MYTH: “Antarctica (and/or the Arctic) are gaining sea ice.” No they are not. There are some small regional or seasonal gains, but these can be explained by melting land ice causing changes in salinity, currents which isolate Antarctica from the warming oceans, and the hole in the ozone layer (which is still there). Like a pot on a stove, global warming increases the energy in the system, which then presents as increased turbulence in both sea and air flows, exacerbated by temperature differentials between air and water at different latitudes (the poles are warming faster than the equator) – see below.
And the latest news from both poles is, frankly, terrifying. More
MYTH: “We had more snow/rain/wind here than usual etc.“ See above. For example the Jet Streams (there are four) are slowing and meandering more because the poles are getting warmer compared with the equator. This can cause unseasonally long periods of unexpected weather – so basically the local weather being worse (or better) does not mean the average temperature of the planet is not increasing. More
MYTH: “We’re approaching a mini Ice Age /Scientists told us in the 70s the world was going to cool.“ Before the full effect of manmade Co2 was properly understood, a few scientists did predict cooling due to solar dimming. But through the 60s and 70s there were only 7 published papers predicting an ice-age, while there were 43 papers in the same period predicting warming. Furthermore, the 7 that were predicting cooling weren’t predicting imminent cooling, just cooling earlier than had been expected. So the idea that the scientific consensus in the 60s and 70s was for cooling is simply wrong. We are in fact approaching a Solar Minimum caused by reduced sun spot activity, so without human emissions we would be in very slow cooling phase – circa 0.2 deg C per 1000 years. This cyclical phenomenon was indeed associated with the last mini ice age, from about 1645 to 1715, but other factors were also in play then, and thanks to global warming no cooling is predicted inside the greenhouse gas layer this time. (And as we saw earlier beyond the layer, the troposphere is, as predicted, cooling, while inside it is heating rapidly).
MYTH: “Sea levels are not rising.” Yes they are, and the latest data suggests a much faster rise then previously predicted. Don’t forget that there are two causes; warmer water is more bulky than cold, and melting land ice flows into the sea making it fuller. (Melting sea ice does not increase sea levels, as you’ll know from your G&T, but it does cause warming, thanks to the Albedo Effect). More.
MYTH: “Temperature measurements are unreliable” (sometimes expressed as “scientists are fiddling the measurements” – this being a misunderstanding of what the word ‘manipulate’ actually means). Almost anywhere you choose to put a thermometer on the surface of the Earth, there’s going to be local factors that need to be taken into account – such as the heat from a city, or ships’ engines etc. Adjusting for this (known as ‘manipulation’ in the trade) is not cheating, it’s good science. See here. Satellite data is more problematic, which helps to explain how ‘the pause’ obtained traction, but once properly processed (aka ‘manipulated’), this data largely supports the surface evidence. See here.
MYTH: “It’s actually atmospheric pressure that’s causing the warming.” Absolutely not.
MYTH: It’s cosmic rays. Nope.
MYTH: It’s the poles shifting: Nah. The lack of evidence for any change in glacial extent associated with the last polar reversal (when magnetic field strength became very weak) makes this highly unlikely. Electromagnetic shifts may be one area where we do need more research, but the idea is clearly, to quote one colleague, a ‘nothingburger.’
MYTH: “You can’t take the average temperature of a system as complex as the biosphere” Well, it’s not easy, but thanks to modern computer modelling we think we can. More.
MYTH: “Climate models are unreliable.” They may not be perfect, but they’re as good as the millions of other models on which most of modern life depends today. There were some minor discrepancies between projections (they are not predictions) made by early climate models and real world observations, which some view as a smoking gun, but in fact this was just normal developmental science in progress. Today the models largely agree with each other and are considered to be robust (and this is not because they’re all based on the same, flawed, data). Bear in mind that any lack of accuracy could just as easily be masking even worse trends (as recent observations do suggest). Remember; “Uncertainty is not a weakness. Understanding uncertainty is a strength, and a key part of using any model, including climate models.” – http://www.demystifyingclimate.org/ More
MYTH: “One degree of warming means nothing when temperatures vary by tens of degrees every season.” It is not one degree in any given place that’s the issue. It’s one degree added to the temperature of ALL the water and gas in the entire biosphere. That’s a MASSIVE LOT of warm (8 zetajules-worth?) – creating a more energetic, turbulent and chaotic system, which holds a lot more moisture to fall as precipitation when the conditions dictate. More
MYTH: “The Hockey Stick was a fraud.” No. It was a best attempt, and it’s stood up very well indeed to scrutiny. Mann has been fully vindicated, exonerated and independently replicated multiple times. More
MYTH: “The UEA Emails prove it was a fraud.” No they did NOT. The UEA’S CRU have also been fully exonerated. They only did not share data because it was not theirs and the people asking for it were clearly seeking to rubbish it from an unqualified viewpoint, and the so-called damning phases like ‘Mike’s trick’ (aka trick of the trade) and ‘hide the decline’ (aka correctly avoid the visual confusion that might be caused by a fully-explained anomaly – NOT hide global cooling), and the rest, did not mean what Steve MacIntyre assumed they meant when he jumped the gun and went off on one.
MYTH: “It’s a political plot (and/or the UN are just promoting socialism, communism, green fascism or worse).“ The IPCC volunteers (there are thousands) merely sum up a vast quantity of authentic independently-funded science, and offer a range of scenarios for others to base decisions upon. If anything, political pressure and the need for agreement would tend to make IPCC reports more conservative than alarmist. As we see below, it actually does turn out that the solutions to climate change can look at first glance more like socialism than neoliberalism, which annoys the right and makes them attack the scientists, but it’s not communism, or even conventional egalitarian socialism, and remember that science is not politics. Don’t shoot the messenger – (and if you’ve been triggered by a hysterical reaction to Agenda 21 / 30 – well, please enjoy and cheerio – you and I have nothing to discuss here). More
Pic: Don Perovich
Boffins in the Back Room
It’s crazy to suggest that climate scientists are somehow too dumb to have thought of these objections, which tabloid writers and bloggers love to claim a child could explain to them. They know them all backwards, and those that are relevant are always taken fully into consideration.
Here is Professor Stephen Schneider answering many of the points above to a theatre-full of doubters, in a wonderfully patient and clear manner, just weeks before he died.
Yet here we are, a decade later, and the same errors crop up time and time again.
Sadly, some would dismiss Stephen and others like him out of hand. This ‘ad hominem‘ habit is both silly and dangerous. If we can’t trust those most expert in this field, regulated as they are by the peer review system, who are we going to trust? People from other disciplines who did not like the way the science was going, and decided to self-educate just enough to blow a likely-looking hole in it? Mining engineers? TV weathermen? Alt-right journalists? Random bloggers? Preppers? The Spiritually Superior?
I think not.
MYTHS: “Scientists are only in it for the money. There is no consensus. There are many thousands of ‘contrary’ scientists. ‘Warmists’ need to shut down the debate, so they just attack anyone who questions them.“
Let’s take these points one by one.
Obviously, if you were only in it for the money, there would be FAR more reward in researching (and/or promoting) ‘business as usual’ than climate change, as many journalists and politicians (and even a few scientists) have found. The bottom line is that for the ‘contrarian/refusenik’ position to hold water, thousands of senior scientists around the world would have to be either stupid, or corrupt, or both.
There is just too much data and expert interpretation (imbued with a healthy level of internal argument I’m glad to say) for the consensus to be explained as mere fund-wrangling. And as for being agents of government – most western governments would greatly prefer easy ‘business as usual’ to difficult decarbonisation, so there’s no incentive for money chasing to do the exact opposite.
In fact one of our senior professors, a solar expert, said to me recently,
“If I could only prove that warming was actually caused by the sun or something rather than CO2, I’d be ecstatic. It would mean a knighthood, a Nobel Prize, and all the funding I’d ever need – for ever! But sadly, I can’t. We’re very confident it isn’t the sun or any of the other ideas that have been floated. CO2 really is by far the most likely cause – it explains the phenomenon very well.”
This established, it’s important to admit that we should not say, as some do, that the science on AGW is settled, because, by definition, science never is. What we can say is that there’s currently a very high level of agreement – a strong consensus – among those fully qualified in this field about where the science of global warming is at the moment.
This said, establishing if there’s a consensus or not within any area of science does not add any extra credibility to that science: It simply informs us about the level of agreement, not about whether or not the science is right per se. That’s determined by the science, the understanding of which may change at any time, as new ideas are pursued and accepted or rejected by other experts.
John Cook from Skeptical Science, suggests a 97% consensus on AGW, which some dispute, often vehemently (it looks about right to me from what I’ve seen on the inside), but regardless of the true percentage, anyone working in the field knows that the science around AGW is now very well established, and that it’s mostly only questioned by, at best, semi-qualified people, using provably weak arguments.
Making this clear, so that we can move on to assessing the relevance of the science, is important, because if at any time someone needs to look at current scientific thinking to inform any political, economic, engineering, medical or other key decision, they need to know the strength of any consensus, and the science it agrees upon, so that this can inform their choices rather than some minority view that happens to appeal to them for some random reason; that way lies risk, error, blame, and repercussion.
There IS a very strong consensus on AGW, which demands urgent action. To ignore or dismiss this is, frankly, irresponsible.
If you still doubt the strength of the consensus or its value to society, talk to any scientist who spends his or her time freezing on the ice, slogging up mountains, lurching on the sea, hacking through jungles, wrestling with Python, juggling with data, yawning at conferences, arguing with colleagues around the world, writing papers, reading papers, writing reviews – as happens every day in our department. They can see what’s really happening out there, and they’re confident they’re on the right track for the causes.
The last point, ‘warmists need to shut down the debate, so they just attack anyone who questions them’ is plain silly.
There’s a big difference between pointing out that someone’s theory is bad science and shutting down the debate (though no doubt it does feel like you’re being shut down when you find your cherished theory does not stand up to expert scrutiny). Science IS debate, by definition.
A few scientists are now speaking out (Michael E Mann most notably – he has good reason to), because they know that the consequences of their work not being taken seriously will be horrendous for mankind. And various writers close to scientists are working hard to explain the science and its consequences, and to explore potential solutions. But that’s NOT shutting down the debate, it’s promoting it.
To be clear, the basic science is accepted by the vast majority: Greenhouse gases cause global warming, and global warming drives climate change. CO2 is a greenhouse gas, and humans are emitting it on an unprecedented scale. And this is making a significant contribution to the measured warming. There is, it’s true, a range of opinion about how much of a contribution humans are making – so the degree of risk is not universally agreed.
The IPCC position, expressed by a range of projections (not predictions, note), is roughly in the middle of this opinion – obviously – because it’s a summary of all of that expert opinion. So, at a risk of being overly simplistic, perhaps we can identify four basic positions:
A (for Antis?) There are a tiny handful of qualified scientists (I don’t include among these all the chemistry teachers and mining engineers and tv weathermen who believe they are experts on climate, but are more obsessed about the size of government or something – and who happen to be good at making YouTube videos), with honestly-held maverick views, which the majority are currently not impressed by but which could and would change the consensus one day IF they can produce evidence / data which can be independently replicated, as all science must be, by definition.
B (for Blasés?) Then there are a few more relatively relaxed climate scientists who are not expecting an apocalypse tomorrow, but who still believe we should decarbonise. These are sometimes called ‘Lukewarmers.’
C (for Conservatives?) The IPCC ‘position’ (endorsed by all major scientific institutions, nearly 200 governments in Paris, and, now, a huge number of corporations – including fossil fuel companies) comes somewhere here. This group is known by the ‘Antis’ as ‘Warmists.’
D (for Doomers?) And finally there are the many deeply worried scientists at the other extreme, who think the situation is already very serious, and that the IPCC position is a dangerous compromise. Now, I can’t give you a percentage, but my genuine feeling is that this is by far the largest group. And that it’s growing – as researchers increasingly find that climate change is happening much faster than the last IPCC summary, AR5, anticipated.
Given that we know that there’s about a 30 year lag in the climate system (so CO2 emitted today will continue to warm the Earth for three decades even if all further emissions were stopped tonight), the precautionary position has to be the only responsible one. (I should mention here that a collegue recently explained that there would in fact be a significant drop in temperature if we did suddenly stop all emissions, but the lag effect would still be significant and persistent).
So given that the IPCC is the only official summary of the science we have, it has to be on IPCC projections that policy must be based.
Arguing against this makes no sense. Decarbonisation is almost certainly a good idea for any number of reasons other than the climate, and if creatively pursued can also give us a healthier economy – as we shall see below.
Global Warming (and Tipping Points)
Some say that the near 1o rise measured since the beginning of the Industrial Revolution is trivial, but actually 1o (which translates to much bigger rises and reductions locally due to the changes it causes in air and sea currents, see above) can mean the difference between water or ice in one place or another. The presence or lack of ice is one of the key factors in the climate system, so this small change can have major impacts not only on local weather, but also on the rate of climate change – especially in terms of potential tipping points (see the ‘albedo effect‘, for example). Remember that it’s the local rate of change that puts pressure on local ecology (small creatures can be very moisture and temperature sensitive when breeding, especially microbes), and therefore on us, as much as the global average change, which affects things like sea level rise. (Melting water ice is not a massive problem of itself because ice displaces water – it’s the land ice that’s the worry – along with the greater bulk of a warmer ocean).
Various projections have been made for the future.
Many believe that 2o (the unofficial target throughout the period between the Copenhagen and Paris talks) is already too hot, risking further damage to ecosystems, limiting agriculture and so causing migration, increasing extreme weather, raising sea levels dangerously, disrupting and even reversing sea and air currents, and possibly even increasing seismic activity due to the release of continents from the weight of ice sheets. All these have happened before, of course (there used to be crocodiles swimming at the North Pole) but then we did not have a complex global infrastructure depending on no change.
The commitments made just before the Paris talks are estimated to deliver about 2.7o of warming, which is certainly too hot for comfort. Of course, at the last minute, the Paris accord did do its best to commit the world to 2o, and even added an aspiration towards 1.5o, which would still be too hot to avoid major problems, but is perhaps achievable – if radical action is taken by every government in the world over the next couple of years. And here is my ex boss Professor Piers Forster on what 1.5 needs to look like here.
But what happens if the world fails to act?
Here again is the scary map published by New Scientist in 2008 which I used in The Urbal Fix, with its prediction of what 4o could look like by 2050: Much of the middle band of the planet has become inhospitable, so humans are having to migrate north or south. Nothing has come along since seriously to dispute this scenario.
Map by Giaia Vince from New Scientist
But, as we heard in The Urbal Fix, many now believe that the rise (if no action is taken) could be as much as 6o , and as Jonathan Porritt says in the film; “6o would be a death sentence for human civilisation. That doesn’t mean to say there won’t be lots of human beings left over after a 6o rise, but I assure you, they won’t be having much of a time.”
And, of course, if certain tipping points are exceeded, it could be even worse than that. Much, much worse:
“ A [small] rise in ocean temperature would melt the ice caps, and cause the release of large amounts of carbon dioxide from the ocean floor. Both effects could make our climate like that of Venus, with a temperature of 250 degrees.” Professor Stephen Hawking
Now, I blame no-one for starting with an opinion that this simply can’t be happening – I thought the same myself for many years. It is just so counter-intuitive that suspicion must be the default position.
But the truth is that major disasters do occur, and they can be huge – witness the poor old dinosaurs. Science is now largely in agreement with Walt Disney – it was indeed an asteroid, and the CO2-induced warming caused by that impact – (the dust did cause an initial global winter, but did not remain in the atmosphere for long), was about the same as is associated with a doubling of energy use from 2009 levels.
IE: Roughly what happens if we fail to implement the Paris Accord, and continue with ‘business as usual.’
IE: Jonathan Porritt’s 6o scenario.
So, frankly, it’s not surprising that so many people are fighting tooth and nail to deny this is happening – after all, as TS Elliott wrote to Tennessee Williams; “Humankind simply can’t bear too much reality.”
But evidence is evidence, and we have plenty.
I’d love to report that my detailed and pretty much constant enquiry into this topic over the past 6 years had reassured me. But it hasn’t. Unfortunately it really does seem we are at the lip of a crisis, and, worrying though that is, climate change is not the only challenge we’re facing.
There are in fact three problems caused by the way we’ve been consuming our home planet. Chief Scientific Adviser to the UK Government, Professor Sir John Beddington, called them The Perfect Storm – a veritable dangling trident of threats; climate change, economic debt-rooted chaos, and rapidly dwindling resources (especially oil, key minerals like phosphorus, clean water, healthy soils) – losses exacerbated by the pollution of what remains. This diagram shows the extent of the problem:
Planetary Boundaries as from The Stockholm Resilience Centre
(The green disc is the ‘safe area’ – the red shows how far we have moved outside it)
Now. We need to be clear, the major threat from climate change is not extreme weather or sea level rise per se, (these could in theory be resisted with existing, if massive, engineering technology) – it is food security, because in spite of all the carbon-emitting, oil and chemical-consuming, polluting new technology, the global food system remains as always totally dependent on a healthy ecological system, something that engineering, even GM, can only hope to tinker with.
These are the countries whose food is most at risk from climate change:
And these are the countries whose emissions are causing the problem – almost a mirror image (and if that doesn’t ask a moral question I don’t know what would):
(Note that India and China, whose emissions are often cited as being a reason why the west should not bother to decarbonise, are shown white. This is per capita emissions – surely the only fair bench-mark, so even with recent new coal-fired power stations, they’re not even on the scale).
Given that there’s a direct link between climate change, food prices and conflict – (there is increasing evidence that the current turmoil in the Middle East has its roots in climate change – also here – as much as in religion, colonialism, corruption and the rest),
(from Prof Tim Benton)
we seem to be looking at a causal chain which goes something like this:
Neoliberalism (the ideology of unregulated markets) > market failures (aka ‘externalities’) > environmental degradation and collapse > food scarcity > starvation > local social unrest > local war > migration > non-local unrest > regional war > further pressure on remaining ecology > etc.
Which is why the New Scientist map above is so scary.
Now, let me say again in big letters, in case you are feeling a little queasy just now;
WE CAN AND WILL FIX THIS!!
But to know what to do, we have first to go back to the beginning, to understand how we got here.
Mind the Mind