Happy New Year to all my readers.

Early in each new year I like to see what the preliminary reports are for the climate over the past year. Final number crunching won’t be available for months, and it may take more than a year for the final tweaks to be reported and reviewed. But we do have a preliminary estimate of the temperature over the last year. The World Meteorological Organization reports:

The global average temperature in 2022 is estimated to be about 1.15 [1.02 to 1.28] °C above the 1850-1900 average. 2015 to 2022 are likely to be the eight warmest years on record. La Niña conditions have dominated since late 2020 and are expected to continue until the end of 2022. Continuing La Niña has kept global temperatures relatively «low» for the past two years – albeit higher than the last significant La Niña in 2011.

It looks like 2022 will be the fourth hottest year on record globally. Some specific locations had their warmest year, such as the UK and Spain (and perhaps most of Europe). As the WMO points out, we are in the middle of a La Niña cycle, which brings cooler temperatures globally. That is a short term fluctuation on the longer term trend. This also means that as we shift into an El Niño cycle we are likely to break new records.

I feel compelled to point all this out (as I am sure many scientists and science communicator will) because it is a critically important piece of information. But I also want to put it into a broader long term context. I have been engaged in skeptical activism now for 27 years, and followed many skeptical topics for longer than that. There is one extremely important pattern that emerges when you cover a topic for a long time – scientifically valid concepts tend to not only accumulate evidence but the evidence gets better and builds on itself. Meanwhile, pseudosciences do not display this pattern. They tend to go around in circles with low quality evidence. You can see this pattern across multiple disciplines.

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Whenever I write about climate change here, the deniers show up spouting dubious (to say the least) claims. In my opinion, this is a manifestation of a deliberate political strategy, one that we see with other topics. The strategy is to make up blatant lies, or at least claims without the slightest regard for whether or not they are true, and then spread them through ideologically friendly outlets. Sometimes this may involve amplifying claims that emerge from the most extreme “fever swamps” promoting that ideology. Just keep throwing crap against the wall, and some of it will stick. When these notions make their way into the mainstream media, they are quickly debunked. But by then it’s too late – the damage is done. Long after the false claims are soundly refuted, the rank and file believers will still be quoting them. They are now part of the narrative.

This means that for science communicators and skeptics (but also mainstream journalists), we need to have a working knowledge of these common false claims that are circulating, so that we can respond to them quickly when they emerge. One of the reasons I allow such comments to continue in my blog is because that is one of the ways that I can see which claims are circulating. I don’t mind if they come here – we can handle it. Normally I handle the claims in the comments, but occasionally there is a critical mass of nonsense that is more efficiently dealt with by a post. Here are some recent claims.

Volcanoes emit more greenhouse gas than human activity.

This is an old one, but has remarkable persistence. These claims go through a selection process. Claims survive not because they are true, but because they resonate. In this case, the volcano claim fits the overall narrative that meager human activity is nothing compared to the awesome scale of nature. They want to portray the very idea that we can alter the climate as ridiculous.  Fact, however, get in the way of this narrative.

According to the US Geological Survey:

Published scientific estimates of the global CO₂ emission rate for all degassing subaerial (on land) and submarine volcanoes lie in a range from 0.13 gigaton to 0.44 gigaton per year.

That sounds like a lot, but human activity releases 35 gigatons of CO2 each year. That means that human activity releases more than 100 times the CO2 as does all volcanic activity. When I pointed this out in the comments, these easily verifiable scientific facts were dismissed as a liberal conspiracy. Another strategy is to simply shift to another claim, without ever admitting that you were wrong on the first one. In this case just shift over to methane – but that is a loser argument also. Of all the methane released into the atmosphere each year, 60% is due to human causes. All natural sources amount to only 40%, and volcanoes are a minority of that. Most methane on Earth comes from biology.

I do admit it still surprises me when this one is trotted out, because these are easily checkable basic facts. This is a good way to completely squander one’s credibility. I think this says something meaningful about the intellectual process that is being employed by those dedicated to the denial of global warming.

Climate models are simplistic and wrong.

Dismissing climate models is a more complex matter to refute, because this is more than just looking up a couple of numbers. First there is the notion that climate scientists, in producing their models which predict anthropogenic global warming, did not consider natural factors. This is, of course, absurd, and represents non-experts criticizing an entire world-wide community of experts from a profound level of relative ignorance – and doing it with confidence and arrogance. This almost always comes without citations, or by citing only known outliers.

Climate models, from the beginning, have sought to include the latest science available and account for all possible factors. Over the last 50 years climate models have been steadily modified, to account for new scientific data as it comes in. In addition, models have to account for future behavior, such as how much CO2 will the world emit in the future. So they can only give ranges of outcomes based upon explicitly stated assumptions about human behavior in the future. Often models are used to project what will happen under various scenarios – continuing our current trends vs changing course.

One of the best ways to determine how well models predict the climate (how “skillful” they are, in the jargon) is to see how past models predicted later climate change. This has been done multiple time. Here is a 2019 review of 17 climate models. They found:

We find that climate models published over the past five decades were skillful in predicting subsequent GMST changes, with most models examined showing warming consistent with observations, particularly when mismatches between model-projected and observationally estimated forcings were taken into account.

That last bit means the difference between projections of CO2 emissions vs actual CO2 emissions. The bottom line is that the model basically work, and they are continuously getting better as they incorporate the latest science. Computers are also getting more powerful, allowing for more complex climate simulations. But still you will frequently hear things like, “Maybe it’s the sun. All those scientists never thought of that.”

A recent commenter brought up one I had not yet heard – neutrinos warming up the inner Earth and all that heat rising to the surface through ocean vents. The commenter also explicitly states that climate models do not include natural sources of warming. Sure, there is geological sources of heat that affect the climate – and climate scientists are well aware of this factor.  Geothermal ocean heating is a known factor. It has a relatively small magnitude, and there is no reason to think that it has suddenly changed in the last 50 years. But the notion that climate scientists are not away of geothermal heating is just silly.

CO2 causes greening which absorbs excess CO2.

The basic notion that increases in CO2 concentrations in the atmosphere increases plant growth is true. CO2 is an important metabolite for plant growth. But the full story is more complicated, and turning this into a net benefit from climate change is simply not true. The increase in productivity does occur, but also results in a depletion of other nutrients, such as nitrogen, from the soil. It therefore is not sustainable in natural settings (i.e. not farmland where nutrients can be added). Also, plants are not adapted to higher CO2 levels and so they get diminishing returns from higher CO2.

But the main reason this is not a valid argument against the need to mitigate climate change, is that it ignores all the other effects. Increasing temperature and worsening droughts are bad for agriculture. Shifting climate also shifts growing zones away from where they are currently located. Also, the effect on different crops varies. Wheat will benefit, but corn production will drop, while some other crops will see no immediate change. This will be highly disruptive to agricultural infrastructure. Also, as warming continues, the effects of increased temperature and drought will overwhelm any positive effect from CO2.

The notion that plants will simply absorb any excess CO2 is also profoundly naive and just factually incorrect. There is a carbon cycle, which already includes plants absorbing CO2. But plants don’t just sequester CO2, they absorb and emit CO2 in a continuous cycle. The more CO2 there is in the system, the more CO2 there will be in every part of the system (plants, the ocean, the atmosphere, in minerals, etc.). This is already accounted for in climate models.

But sure, we should maximize biomass to help mitigate CO2 release, and stop doing things like cutting down the rainforest. But this is not going to compensate for the 35 billions tons of CO2 humans release every year.

Europe is experiencing an extreme heat wave, with the UK set to reach the highest temperatures ever recorded there in the 363 years it has been keeping records. The current hottest temperature recorded in the UK was in 2019 at 38.7 C. The top ten hottest years have all been since 2002. Now the UK is predicted to hit 40-41 C in the current heat wave, and have already hit 37.5 C.

This should come as a surprise to exactly no one. Of course, weather is not climate, and heat waves happen. No one heat wave is evidence of climate change, the same way a cold day in December is not evidence that the planet is not warming. We have to look at global temperatures in aggregate, but also global warming does increase the probability of things like heat waves, droughts, and fires, and how extreme they are. There are also separate reasons why Europe in particular is seeing extreme heat waves, but this only explains why Europe is especially vulnerable, not why the heat waves are happening at all.

Science is also confirmed by how well it makes predictions. If we go back 20 years, the climate change denial community was claiming that global warming had “paused”. They used this claim to bolster their bigger claim that climate change was not happening at all, that we were just looking at a natural variability in climate that was regressing to the mean. The next 20 years, they predicted, would see a return to more historically average temperatures.  Meanwhile, scientists were predicting that global warming trends would continue. They predicted that the next 20 years would see increasing average temperatures, more hottest years on record, more heat waves and droughts.

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What if there were a change we could make in our society that would save, in the US alone, more than 50,000 lives per year and avoid more than $600 billion every year in health care costs and lost productivity? How much should we invest each year to make the necessary changes? Even if we invested $3 trillion over the next 10 years, that would only be half as much as we would save over the same length of time (in addition to preventing have a million premature deaths). Would you say that was worth it? It sounds like a good deal, but of course we have to delve into the details.

I am talking, as you probably guessed from the title, about clean energy. Burning fossil fuels releases particulate matter into the atmosphere, which causes respiratory illness and increases the risk of stroke and heart attack. Coal is worse than oil is worse than natural gas, but they are all a problem. A newly published study set out to estimate the societal costs just from the perspective of health to the energy, transportation, and manufacturing industries and their use of fossil fuel. Here are the key findings from the abstract:

In this study, we estimate health benefits resulting from the elimination of emissions of fine particulate matter (PM2.5), sulfur dioxide, and nitrogen oxides from the electric power, transportation, building, and industrial sectors in the contiguous US. We use EPA’s CO-Benefits Risk Assessment screening tool to estimate health benefits resulting from the removal of PM2.5-related emissions from these energy-related sectors. We find that nationwide efforts to eliminate energy-related emissions could prevent 53,200 (95% CI: 46,900–59,400) premature deaths each year and provide $608 billion ($537–$678 billion) in benefits from avoided PM2.5-related illness and death. We also find that an average of 69% (range: 32%–95%) of the health benefits from emissions removal remain in the emitting region.

Even if these estimates are off by a factor of two or three, which is unlikely, we are still talking about 2-3 hundred billion dollars per year. Therefore, from a purely economic perspective, investing in clean energy is a good deal for the US, its people, and our economy. It would be economically irresponsible if we did not heavily invest in making the transition to clean energy as quickly as possible. It is important to realize the bottom line here – we can justify heavy investment in clean energy just from a health and health-related cost perspective alone. Even if you are a denier of global warming and its impacts, you should still support clean energy and rapidly phasing out fossil fuels.

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While the world debates how best to reverse the trend of anthropogenic global warming (AGW), scientists continue to refine their data on historical global temperatures. A recent study published in Nature adds to this a high resolution picture of average surface temperatures over the last 24,000 years, since the last glacial maximum. The study reinforces the conclusion that the last century of warming is unprecedented over this time frame, and does not reflect any natural cycle but rather the effects of human forcing.

To construct their map of past temperatures, the researchers combined two methods. They used a dataset of chemical analysis of marine sediments, which are affected by local average temperatures. They combined this with a dataset based on computer-simulated climate models. The idea was to leverage the strengths of each approach to arrive at a map of historical surface temperatures that is more accurate than either method alone.

Of course, no one study is ever the final word, but this reconstruction is in line with other research using independent methods and data. The authors also draw two other main conclusions from their data. There has been a debate about whether or not the last 10,000 years had a small warming trend, and this graph supports that conclusion. Further, the authors conclude that the main driver of the large warming trend starting around 17,000 years ago is the retreat of the glacial ice sheets, but that the main driver of the rapid warming over the last 150 years is increasing green house gases. The rate of this recent warming is also out of proportion to any natural cycle detected in the last 24,000 years.

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Next month the UN will host the 26th conference on climate change, the COP26. At this point the discussion is not so much what the goal should be, it’s how to achieve that goal. The Paris Accords set that goal at limiting global warming to 1.5 C above pre-industrial levels. In order to achieve this outcome goal the consensus is that we need to achieve the primary goal of net zero green house gas (GHG) emissions by 2050. There is considerable disagreement about whether or not net zero by 2050 will achieve the outcome goal of limiting warming to 1.5 C. Some experts think it’s already too late for 1.5 C, and we should be planning on at least 2.0 C and what the world will be like with that much warming.

Either way, there is agreement that we should focus instead on what we can actually do, achieve net zero by 2050, rather than the outcome which we cannot predict with that level of precision. If we agree on this goal, the conversation then shifts to the question of how we can achieve this goal. From one perspective the answer is easy – we need to stop burning fossil fuels, convert those industries with the greatest carbon footprint to produce less CO2, and add some carbon capture to compensate for whatever CO2 emissions we cannot fully get rid of. But that’s like saying – in order to win football games you need to score more points than the other team, mostly through touchdowns and field goals. That’s correct, but doesn’t really give you the information you need. How, exactly, will we achieve these ends?

This is the conversation we should have been focusing on for the last 20 years, rather than dealing with denialists who refuse to accept the scientific reality, or the delay tactics by industry and their paid representatives (i.e. politicians). It’s pretty clear at this point we are never going to convince the deniers (not in this political climate – and I’m sure the comments to this post will adequately demonstrate my point), and industry is going to run out the clock any way they can. The bottom line is that achieving net zero by 2050 will require leaving fossil fuels in the ground, unburned. For the fossil fuel industry this means leaving a lot of money on the table, which is not going to happen simply out of a desire to be good corporate citizens.

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Syukuro Manabe, Klaus Hasselmann, and Giorgio Parisi share this year’s Nobel Prize in Physics for their work increasing our understanding of how complex systems work. This is a powerful tool for understanding the world, which reminds me of previous advances in our understanding of how gases behave.

Gases are a phase of matter in which high energy particles are bouncing around at random. It would be impossible to predict the pathway of any individual gas molecule. However, collectively all of this random complexity follows very predictable laws. Similarly, weather is a very complex system. We can predict weather that is about to happen, but beyond a few days it becomes increasingly difficult. The system is simply too chaotic. However, climate (long term weather trends) follows theoretically predictable patterns. The trick is to see the hidden patterns in the chaos, and that is the work that these three physicists did.

Manabe and Hasselmann share half the prize for their work on climate models:

Syukuro Manabe demonstrated how increased levels of carbon dioxide in the atmosphere lead to increased temperatures at the surface of the Earth. In the 1960s, he led the development of physical models of the Earth’s climate and was the first person to explore the interaction between radiation balance and the vertical transport of air masses. His work laid the foundation for the development of current climate models.

About ten years later, Klaus Hasselmann created a model that links together weather and climate, thus answering the question of why climate models can be reliable despite weather being changeable and chaotic. He also developed methods for identifying specific signals, fingerprints, that both natural phenomena and human activities imprint in the climate. His methods have been used to prove that the increased temperature in the atmosphere is due to human emissions of carbon dioxide.

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It is not uncommon, if you do not like any particular finding of scientific research, to attack the institutions of science or even the very notion of science itself. These kinds of attacks are now common in the anti-vaccine pushback against common sense public health measures, and often from a religious or ideological perspective. It’s not surprising that the false claim that science is just philosophy has reared its head in such writings. The attack on science also tends to have at least two components. The first is a straw man about how scientists are pretending that science is a monolithic perfect and objective entity. This is then followed by the claim that, rather, science is just opinion, another form of subjective philosophy. This position is entirely wrong on both counts.

Here is one example, embedded in a long article loaded with misinformation about vaccines and the COVID pandemic. There is way too much misdirection in this article to tackle in one response, and I only want to focus on the philosophical claims. These are now common within certain religious circles, mostly innovated, at least recently, in the fight against the teaching of evolution. They have already lost this fight, philosophically, scientifically, and (perhaps most importantly) legally, but of course that does not mean they will abandon a bad argument just because its wrong.

First the straw man:

The second consequence of “following science” is that it reinforces one of modernity’s most enduring myths: that “science” is a consistent, compact, institutionally-guaranteed body of knowledge without interest or agenda. What this myth conceals is the actual operation of the sciences—multiple, messy, contingent, and tentative as they necessarily are.

The myth is itself a myth. It exists almost nowhere except in the minds of science deniers and those with an anti-science agenda. Elsewhere the author admits:

As a lay person, unqualified to judge the technical issues, I have concluded only that there might be a legitimate question here, and one that must, necessarily, remain open until time and experience can settle it.

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The Intergovernmental Panel on Climate Change (IPCC) has just produced their sixth report. This report builds on their previous work, and the current version (AR6) is the product of 234 scientists from around the world. This is essentially an update from their previous reports, taking into account all new evidence that has come to light. You can read the full report, or the executive summary for policymakers, or if you want more detail, the technical summary. Many news outlets, like the BBC, have also put out a highlight summary of their own.

I am not going to produce my own summary, just read the executive summary if you want the details. It’s only 39 pages. Instead, I am going to make some general observations.

First, for those who say there is no such thing as consensus in science, you are straight-up wrong. That is a strawman and denialist talking point. The strawman is the ubiquitous talking point that science is not determined by consensus. Of course it isn’t – consensus is determined by the science. The IPCC report is a great example of what consensus in science means – 234 experts pour over all the available evidence and then hash out a joint statement about what that evidence says. Next to each and every point there is a confidence notation, which they quantify – unlikely, likely, very likely, etc., with percentage confidence indicated for each notation. They are acknowledging the uncertainty, which torpedoes another strawman, equating consensus with certainty, or that the science is “settled” or that further research or debate is being shut down. This is all nonsense. The IPCC is simply a list of specific scientific statements, with a summary of the current evidence and degree of confidence.

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It has become a mantra of climate scientists that global warming is just what it says – global. It is a statistical average over time. It cannot be tied to any specific weather event, even if it predicts that statistically such events are more likely. However, the current heat wave in the North American Northwest is so statistically extreme, that climate scientists are discussing it in very different terms. For example, the BBC reports: