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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.
Explaining climate change science & rebutting global warming misinformation
Global warming is real and human-caused. It is leading to large-scale climate change. Under the guise of climate "skepticism", the public is bombarded with misinformation that casts doubt on the reality of human-caused global warming. This website gets skeptical about global warming "skepticism".
Our mission is simple: debunk climate misinformation by presenting peer-reviewed science and explaining the techniques of science denial.
This is an updated version of Analogy 1, which illustrates the impact of the rate of increase of CO2 on the natural world's ability to adapt. The original version is here.
Tag line
Speed Kills
Elevator Statement
Deceleration from 60 mph to 0 in …
30 seconds (base rate): Normal exit from a freeway; no drinks spilled; life goes on.
3 sec (10 times base rate): Slam on the brakes. Loose items end up on dashboard. Those not wearing seat belts do ungraceful face plants. Survivable injuries.
0.3 sec (100 times base rate): Like running into a parked car. Crumple zones in both cars absorb much of the energy, but people are seriously injured, some mortally.
0.03 sec (1000 times base rate): Like running into a brick wall. You get the point.
Climate Science
Increasing atmospheric CO2 concentrations cause global warming. Global warming drives climate change. The rateof increase of CO2 concentration is important, because it determines the rateof global warming, and therefore the rate at which natural systems must adapt. Figure 1 shows CO2 concentrations from the end of the recent ice age to the present. Think of Fig. 1 as the Keeling Curve with historical context, illustrating how rapidly CO2 is rising relative to the most recent deglaciation rate. If we limit the rate of increase of CO2 to that experienced during a deglaciation cycle, we expect nature will adapt; the further away we move from this base rate the more difficult it is for nature to adapt, because rapid rises of temperature are often associated with extinction events.
Figure 1. Rate of increase of CO2 relative to the rate during the recent deglaciation. The animals running up the CO2 "hill" indicate that nature can adapt to this rate of change. A stable CO2 level provided a relatively stable climatic base for the development of modern civilization. Can modern civilization surmount the CO2 cliff in front of us? (Clipart licensed from iStock/skalapendra (car), iStock/blueringmedia (herd), Getty Images/zaricm (caveman), and 123RF/Lorelyn Medina (chariot))
Almost 10% of the 8 billion people on earth are already undernourished with 3 billion lacking healthy diets, and the land and water resources farmers rely on stressed to “a breaking point.” And by 2050 there will be 2 billion more mouths to feed, warns a new report from the United Nations Food and Agriculture Organization (FAO).
For now, farmers have been able to boost agricultural productivity by irrigating more land and applying heavier doses of fertilizer and pesticides. But the report says these practices are not sustainable: They have eroded and degraded soil while polluting and depleting water supplies and shrinking the world’s forests. The FAO report discusses some important climate change impacts, such as changing distribution of rainfall, the suitability of land for certain crops, the spread of insects and other pests, and shorter growing seasons in regions affected by more intense droughts. While not the sole source of obstacles facing global agriculture, the report makes clear that climate change is further stressing agricultural systems and amplifying global food production challenges.
The report also offers hope that the problems are solvable: Water degradation can be reversed by turning to smart planning and coordination of sustainable farming practices and by deploying new innovative technologies. More sustainable agriculture can also help fight climate change: For instance, the report notes that wiser use of soils can help sequester some of the greenhouse gasses currently emitted by agricultural activities.
Drastic changes in climate will require regions to adjust the crops they grow. For example, the report predicts that much cereal production will probably have to move north, to Canada and northern Eurasia. Brazil and northern Africa may have a harder time growing coffee, but it may get easier in eastern Africa. A changing climate “may bring opportunities for multiple rainfed cropping, particularly in the tropics and subtropics.” And for areas “where the climate becomes marginal for current staple and niche crops, there are alternative annual and perennial tree crops, livestock, and soil and water management options available.”
The report recommends seed and germoplasm exchanges globally and among regions, and investments to develop crops that can withstand changes in temperature, salinity, wind, and evaporation.
The changes will not be easy, the report says, but they may be necessary to avoid widespread hunger and other catastrophes.
By the end of the Sunday, January 9, Don’t Look Up, writer-director Adam McKay’s dark satire about the impending impact of an Earth-killing comet, intended as an analogy for inaction on climate change, had been streamed on Netflix for a total of 322 million hours, putting it within striking distance of the most-watched movie in the platform’s history.
Dividing that imposing number by the film’s running time (2 hours and 18 minutes) provides a high-end estimate of the number of viewings: 140 million. That’s 51 million more than the number of people who bought tickets to see Roland Emmerich’s The Day After Tomorrow (Day After) during the entirety of its 2004 run. In other words, in just three weeks Don’t Look Up has eclipsed Day After as the most widely viewed fictional film treatment of climate change.*
But Don’t Look Up’s run isn’t over. On January 7, McKay’s production company, Hyperobject Industries,** released the first two episodes of its podcast about the making of the movie, The Last Movie Ever Made. The company plans to release four more episodes, one each week until Friday, February 4. By continuing to provide new material for discussion, through the podcast and his tweets and blog posts, McKay is likely to keep people talking about, and watching, Don’t Look Up.
In fact, the discussion among film critics and fans is already quite lengthy and animated, another metric by which Don’t Look Up has matched or surpassed the impact of Day After. (See this site’s accounts of the production and reception of Day Afterhere and here.)
Since the film’s limited theatrical release on December 10 (its Netflix run began on December 24) YCC has identified 59 reviews of Don’t Look Up, of which 35 were mostly positive (59%) and 24 mostly negative (41%). This slightly more positive ratio – Rotten Tomatoes had a positive score of 55% – likely reflects the inclusion of later, more personal reactions to the film by climate scientists and activists who objected to the early, often dismissive reviews. (Readers can find Yale Climate Connections’ review of Don’t Look Uphere.)
Posted on 20 January 2022 by Doug Bostrom, Marc Kodack
Cloud tops fade from sight at a critical juncture
Employing the Earth orbiting instrument MISR, Travis Aerenson et al. appear to confirm subtle hints by prior observations tracking what climate models broadly predict: a gradual increase in the topping altitude of high clouds. Their paper When Will MISR Detect Rising High Clouds (pdf) details this work. This seems an important finding, as high clouds have a significant positive feedback effect on Earth's surface temperature. The article shines in offering a full education on the subject via references, but in a nutshell these clouds rising still higher produce the net effect of impeding the escape of longwave radiation, making our original CO2 problem worse.
The authors find this initial detectable signal in clouds over the oceanic southern hemisphere. With modeling they show that emergence of this feature in the tropics and northern hemisphere may be imminent, within 3-10 years. This is a significant claim surely deserving of attention and further scrutiny.
The awful rub of this situation is that MISR is carried by the Terra (pdf) satellite, launched in 1999 and with the expenditure of its last normal station-keeping reactant budget early last year no longer able to maintain a precisely controlled orbit. As well, with age (plus damage from an earlier likely orbital debris strike) the spacecraft's batteries are failing. It's highly unlikely the MISR instrument will be able to carry on with observations as the predicted emergence of ascending cloud tops in other regions become visible.
Ignoring the concerning nature of apparent confirmation of a feedback effect, MISR and Terra serve as yet another object lesson on effects of governmental inability to maintain long attention and funding spans colliding with crowded research agendas. Together these make impossible true operational Earth observational systems of the type we absolutely require. The immediate situation's root causes are akin to the recent GRACE data gap, a longitudinal series interrupted and hence needing inherently imperfect splicing. There is a relatively paltry lack of money forcing bad choices on researchers. A copy of the first GRACE duo should have been available for orbital deployment before the next more refined version was developed. Instead as a matter of fiscal reality new research ends up competing with mandatory operational needs.
We can't afford to continue making mistakes. Observations of the type made by MISR are not purely scientific in nature but are also akin to instrumentation on an engine. If an idiot light burns out on our car's dashboard, we can replace it easily and quickly. MISR and GRACE— examples of key instrumentation of critically important Earth systems— are more important than idiot lights.
Ideally our policy would be to quickly identify experimental instruments that reveal themselves as potentially important operational features and then to ensure that this equipment is practicably available for continuous coverage. In particular, it seems perhaps wise to think about achieving some economy of scale, reduce the need to constantly produce novel space-qualified hardware. Instead, think more along the lines of meteorological radiosondes. Radiosondes are not redesigned for every launch. The benefits of accomodating this "boredom" are plain to see. In turn, such a pragmatic approach could make congressional relations in seeking operational budgets easier.
Obviously radiosondes are a different case than orbital instrumentation. But with the first copy of an instrument costing so much compared to duplicates and with spacecraft buses far past the point of needing reinvention for each launch, perhaps it would be good to heavily emphasize in planning decisions "is this experimental package likely to be operationally beneficial?" Then, accomodate in plans routine operation of a given instrument package— including timely orbital replacement— commensurate with that estimation, at the earliest stages of development. Most of all, see and avoid the potential folly of spinning up tooling, skills and vendors to produce only a single copy of an instrument— very expensively. That's a mistake we've already made and we needn't continue repeating.
Top Risks 2022 (pdf) in our government/NGO report section describes awkward details of our "today" energy economy colliding with urgent requirements to shift to tomorrow's.
2022 is already feeling as stressful as the worst stretches of 2021 – and without the prospect of a fresh start with a new administration.
Newscasters report that COVID-19 cases are arising at three times the rate posted during the peak of last summer’s wave. And on TV, phone, and computer screens, first-anniversary autopsies of the Jan. 6th attack on the Capitol are repeatedly streaming videos of angry Trump supporters breaking windows and battering security officers.
Everyone needs a break, some comic relief.
Don’t Look Up, the new star-studded comedy directed by Adam McKay and now the most watched film on Netflix, seems the perfect remedy. It’s even billed as a climate film. Should YCC readers see it?
That depends – on their solar plexuses.
The film has been widely promoted as a kick-in-the-pants send-up of American inaction on climate change. But what the two-plus hour film actually delivers is a kick-in-the-stomach depiction of America’s narcissistic (social) media and its dysfunctional politics. Like this critic, some viewers may finish the film feeling even more pessimistic about the prospects for real action on climate change. But they may also realize something important in the process.
The city government of Manchester, England is coming under some fire for choosing to lease space on pavements (also known as sidewalks) for electronic display advertisements, or "digital out of home advertising." Criticism is twofold in nature. Some point out that crowding of pavements with bulky fixed installations is an insult to pedestrians. Others are looking at the problem a different way, at how this choice boosts energy consumption.
How much energy? Quite a bit.
"According to analysis of data revealed by a freedom of information request, each of the 86 digital advertising boards in Manchester city centre uses 11,501kWh of electricity every year."
It seems an awfully large number, perhaps even wrong. But it works out to about 1.3kW to power each sign. Not difficult to achieve if nobody is thinking about efficiency at any point in the design and decision process leading to signs planted on pavements.
Manchester's city council declared a "climate emergency" in 2019. In the face of that, energy profligacy to the tune of 11.5kWh to run a single sign for a year should be more than conspicuous but even unthinkable. If we think of "climate emergency" as something akin to "war emergency," take this matter seriously and are not only paying lip service, very hungry twinkling signage is indeed a puzzling choice to make. How do Manchester's leaders feel they're guiding their constituents to victory with choices to burn more energy for no particularly compelling reason?
And by extension and not to unfairly pick on Manchester, if by "we" we mean voting constituencies in general, many of us are tolerating this type of undermining behavior in the face of disaster.
But we need to see what poor decisions look like, understand how and why thoughtless behavior can add up to large numbers, and how being oblivious has ripple effects. Knowing those things, we can identify options for tuning, ways of coming to at least a partial solution to something that unfortunately— due to matters unrelated to climate— does have something of the nature of a dilemma to it.
Tradeoffs are required, but happily there's likely room for productive trading.
Getting skeptical about "renewable = panacea"
Facing criticism over energy waste, Manchester's city government immediately deployed the "no worries it's renewable power" card. At 11.5 MWh/year of electrical consumption to power each sign, the situation affords a nice opportunity to interrogate "it's ok, it's powered by renewables," an easy excuse to make but one that can support only a limited number of confused or deeply motivated thinkers leaning upon it.
The year 2021 made an indelible mark in the annals of weather history. Not only did it feature the most extreme heat wave in history – the late June heat wave over western North America that smashed all-time records by unprecedented margins – it also had four weather mega-disasters costing over $20 billion each, tied with 2017 for the most such disasters on record.
Figure 1. Time series of global weather mega-disasters costing at least $20 billion (adjusted to 2021 dollars). Data for the U.S. is from NOAA; data for the rest of the world is from the international disaster database, EMDAT. There has been a concerning rise in these mega-disasters in recent years, as evidenced by the blue linear trend line, and 2021 had the most on record: four. Note that the database from insurance broker Aon has at least one $20+ billion-dollar event not in the EMDAT database: monsoon flooding in China that cost $35 billion in 2020.
About $39 trillion – that’s trillion, with a T – is the total some 1,500 institutions are planning to divest from funds in fossil fuels. And those numbers are growing.
The Global Fossil Fuel Divestment Commitments Database, maintained by two nonprofit divestiture advocacy groups, Stand.earth and 350.org, tracks institutions that have pledged to divest from fossil fuels fully, partially, or with regard to certain subsets, such as coal. The roughly 1,500 institutions include pension funds, governmental, philanthropic, faith-based, and educational institutions, and others.
Faith-based organizations comprise the single largest group at about 35% of the total, followed by educational institutions (nearly 15%), philanthropic foundations (12.6%), pension funds (11.8%), governments (11.4%), and for-profit corporations (8.7%).
Calling climate change “the most consequential threat facing humanity,” and pointing to a “need to decarbonize the economy,” Harvard University President Lawrence Bacow in September 2021 called an end to the university endowment’s “direct investments in companies that explore for or develop further reserves of fossil fuels.”
Divestment advocates, including a coalition called Divest Harvard, had pushed for the university to divest for nearly a decade. “It was a great triumph of a decade-long struggle by thousands of students and lots of faculty and alumni,” author, writer, and 350.org founder Bill McKibben chimed in, commending their “perseverance.”
Nearby Boston University soon followed suit, joining universities, including Brown, California Institute of the Arts, Columbia, Cornell, George Washington, Georgetown, Oxford, Rutgers, Syracuse, and many others in the U.S. and around the world. (Details on Yale University’s fossil fuel investments policy are here and on its implementation of those principles here.)
Posted on 13 January 2022 by Doug Bostrom, Marc Kodack
Geoengineering five minute university
Not long ago we added a new section to New Research for select reports and reviews from governmental agencies and NGOs, material not within our original remit of peer reviewed research articles published in academic journals. Thanks to their typical target audience of nonspecialists, these publications are often an excellent way to quickly come up to speed on major salient features of a given knowledge domain.
A few minutes spent on RAND's quickly informative "executive summary" of geoengineering science and technology will immediately lead any thinking person to realize that we're looking at a veritable Pandora's box in terms of "secondary effects," or how RAND delicately expresses "blowback."
At this juncture we may not want to foreclose reaching into this box of tools but we'd best be forearmed in imagining ways doing so could go wrong. The report goes on to describe potential scenarios of unilateral engineering efforts and how those might be checked or at least managed. We don't have to invent governance from whole cloth, fortunately. RAND illustrates several tried and more or less true frameworks for creating legal or at least normative mechanisms to help make geoengineering less risky, if or when it should become a less abstract matter. RAND concludes by suggesting we may best be making policy before the geoengineering horse escapes the barn.
Cranky Uncle uses cartoons, humor, and logic-based inoculation to build resilience against misinformation – an ideal tool for teaching critical thinking to students. This page features resources for educators interested in using Cranky Uncle (the game or the book) to teach critical thinking in their classes. For starters, the game is freely available on iPhones, Androids, and browsers (e.g., for anyone with internet access):
This blog post provides an overview of resources for educators about how the Cranky Uncle game can be used in the classroom. We will update the article as additional resources become available.
“Keep 1.5 alive” emerged as the haunting refrain of the recent United Nations climate conference in Glasgow. Although a well-intentioned rallying cry, it raises important questions about how the chant is to be interpreted. Unfortunately, 1.5° centigrade is often presented as an immutable crisis point, rooted in established scientific consensus. It’s implied that beyond this point, climate-induced damages increase dramatically.
Given the prospect that the 1.5°C target may not be met, proponents might come to rue their choice of mantra. Not only will it likely cause unnecessary despair, but oversimplification of the underlying science provides those resolutely opposed to acting on climate change with opportunities for further mischief.
This is not to argue that danger points don’t exist. There is ample evidence in paleoclimate records of sudden and dramatic shifts in Earth’s climate system, though the conditions that triggered them are not fully understood and are not directly comparable to present-day conditions.
Another reason for concern comes from computer models of the climate system. Models also alert us to the possibility that continued warming may cause rapid climate changes that cannot be easily reversed for centuries or longer. Examples of such changes include abrupt sea-level rise and slowing or even shutdown of a key part of the ocean’s system for circulating heat. While few studies suggest that these changes are imminent, models and “deep time” climate records both tell us that somewhere out there, beyond the 1.1°C of warming experienced to date, dangerous tipping points exist. We don’t know exactly where they are, just that further warming makes it more likely we will cross them.
But for the moment forget things like the Christmas, Hannukah, and New Years holidays. And set-side briefly the frightening wind-blown fire that ravaged parts of Colorado near Boulder; the sudden early January heavy snowfall that blanketed the Mid-Atlantic and left hundreds (including U.S. Senator and one-time Vice-Presidential candidate Tim Kaine) abandoned on one of the nation’s most heavily travelled interstates – I 95 from Washington, D.C., area south to Fredericksburg, Virginia; the sub-zero temperatures in Montana and parts of the upper Midwest.
Fuhgeddaboudit. Though only for long enough to check independent videographer Peter Sinclair’s new Yale Climate Connections video on the “first-ever” extreme tornadic activity that grabbed national headlines and prime-time network and cable coverage for days in – get this – in December, no less.
Posted on 6 January 2022 by Doug Bostrom, Marc Kodack
Incidental rainmaking with utility-scale PV?
Ths week's geoengineering section includes an article that focuses not on planetary cooling but instead a surprising possible feature of decarbonization, for certain circumstances. The analysis treats a particular geographic context and so it's not possible to say how widely it could be replicated. Even so, the idea that significantly positive increases in rainfall in a part of the world very much in need of more rain could be a side-effect of large scale photovoltaic power installations is not only quite surprising but also quite tantalizing. In this case, it seems possible that at PV plant scales the authors concede are large, water sufficent for the needs of 2.5 million people could be delivered by rainfall to areas already having catchment and reservoir capacity to gather and store it. Sea Breeze Geoengineering to Increase Rainfall over the Arabian Red Sea Coastal Plains (pdf) published in the AMS Journal of Hydrometeorology by Suleiman Mostamandi et al. explains how this may be possible. Open access and free to read.
'Alarming' recent change in an important river
Irina Panyushkina et al. identify evidence of very recent and large differences in the behavior of the largest river draining into the Arctic Ocean, in Unprecedented acceleration of winter discharge of Upper Yenisei River inferred from tree rings (pdf), published in Environmental Research Letters. Paying careful attention to details of climate influences on ring growth, the authorsvastly extend the paleohydrographic record for the Yenisei, deep into the 18th century. They find no precedent in the past 214 years for sudden changes in very recent years, specifically an increase of 80% in winter surge flows. Permafrost melting and warming-induced fires appear to drive this and ultimately result in yet another unfortunate feedback process. The article is open access and free to read. From the abstract:
We discuss the impact on the baseflow rate change of both the accelerating permafrost warming in the discontinuous zone of South Siberia and widespread forest fires. The winter discharge accounts for only one third of the annual flow, yet the persistent 25 year upsurge is alarming. This trend is likely caused by Arctic Amplification, which can be further magnified by increased winter flow delivering significantly more fresh water to the Kara Sea during the cold season.
90 articles in 36 journals by 531 contributing authors
Wildfires that swept through Sequoia National Forest in California in September 2021 were so severe they killed ancient trees that had adapted to survive fires. AP Photo/Noah BergerShuang-Ye Wu, University of Dayton
Alongside a lingering global pandemic, the year 2021 was filled with climate disasters, some so intense they surprised even the scientists who study them.
The area around Boulder, Colorado, was so unusually dry on Dec. 30, 2021, that a powerful wind storm sent grass fires racing through neighborhoods in Superior and Louisville, burning hundreds of homes in a matter of hours. Officials said the winds were so strong, there was little firefighters could do but evacuate homes and businesses in the fires’ paths.
In the U.S. alone, damage from the biggest climate and weather disasters is expected to total well over US$100 billion in 2021. Many of these extreme weather events have been linked to human-caused climate change, and they offer a glimpse of what to expect in a rapidly warming world.
In the U.S., something in particular stood out: a sharp national precipitation divide, with one side of the country too wet, the other too dry.
As a climate scientist, I study the impact of global warming on precipitation and the water cycle. Here’s what happened with precipitation in the U.S. in 2021 and why we’re likely to see similar scenarios in the future.
Lots of people embrace New Year’s as a time to commit to exercising, getting organized, or saving money.
“It’s a very strong symbolic moment where people resolve to make changes in their lives,” says Daniela Tejada of the “Count Us In” campaign.
She says New Year’s is the perfect occasion to commit to helping reduce climate change.
“Count Us In” is an online platform where people pledge to take specific actions to reduce carbon pollution. For example, participants make lifestyle changes such as turning down the thermostat or driving less, or they encourage their policymakers to take climate action.
“We want to make sure that individuals are empowered to take action that’s practical and impactful,” Tejada says.
She says that since the project launched in 2020, about 200,000 people have made a pledge.
And now, the campaign is partnering with “Don’t Look Up,” Adam McKay’s new movie on Netflix, to encourage viewers to get involved.
Tejada says that together, people’s individual actions can add up to significant cuts in carbon pollution.
And she says that the pledges send an important signal to policymakers and business leaders: that voters and consumers are serious about reducing climate change, and they should get serious, too.
With each tragic event comes the question of whether human-caused climate change made it more severe or more likely. The burgeoning field of climate change “attribution” has stepped up to the challenge. While 10 years ago it might have taken months to fully analyse an individual weather event, scientists are now able to provide an answer in just days or weeks.
Because we cannot make direct observations of a world without human influence on the climate, all attempts to answer this question involve some kind of modelling. However, traditional climate models can struggle to simulate the most extreme weather events. To deal with these compromises, researchers have traditionally relied on comparing results from several different approaches to assess the robustness of their conclusions.
We suggest that a better approach would be to use numerical models that have demonstrated their ability to simulate the event in question through a successful – or at least reliable – weather or seasonal forecast.
In our recent study, published in the Proceedings of the National Academy of Sciences, we demonstrate – for the first time – an attribution study that uses a state-of-the-art operational weather forecast model. We tested our approach by assessing the European winter heatwave of 2019 – an event the model successfully predicted.
We find that the direct impact of the extra carbon dioxide (CO2) that humans have pumped into the atmosphere made the event 42% more likely for the British Isles and at least 100% (two times) more likely for France.
Listing of articles linked to on the Skeptical Science Facebook Page during the past week: Sun, December 26, 2021 through Sat, January 1, 2021. This being the final installment for 2021, I'd be interested to know how helpful this summary blog post is, so please leave a comment if you check any of the mentioned articles. Thanks!
Arguments
Wildfires that swept through Sequoia National Forest in California in September 2021 were so severe they killed ancient trees that had adapted to survive fires. 
