The big tornado outbreak, including a monster Oklahoma twister, have people asking again about a possible link to climate change. I’ll review the science in this post.

“The news helicopter from kfor.com caught this image of the shocking near-total destruction of a huge area of Moore, Oklahoma, on May 20, 2013.” Via Masters.

Tom Karl, the director of the National Climatic Data Center, explained in a 2011 email:

What we can say with confidence is that heavy and extreme precipitation events often associated with thunderstorms and convection are increasing and have been linked to human-induced changes in atmospheric composition.

Insured losses due to thunderstorms and tornadoes in the U.S. in 2012 dollars. Data and image from Property Claims Service, Munich Re.

Tornadoes “come from certain thunderstorms, usually super-cell thunderstorms,” explained climatologist Dr. Kevin Trenberth in an email today, but you need “a wind shear environment that promotes rotation.” Global warming may decrease the wind shear and that may counterbalance the impact on tornado generation from the increase in thunderstorm intensity.

Trenberth, the former head of the Climate Analysis Section of the National Center for Atmospheric Research, notes:

The main climate change connection is via the basic instability of the low level air that creates the convection and thunderstorms in the first place. Warmer and moister conditions are the key for unstable air.

The climate change effect is probably only a 5 to 10% effect in terms of the instability and subsequent rainfall, but it translates into up to a 32% effect in terms of damage. (It is highly nonlinear). So there is a chain of events and climate change mainly affects the first link: the basic buoyancy of the air is increased.  Whether that translates into a super-cell storm and one with a tornado is largely chance weather.

After April 2011 saw records set for most tornadoes in a month and in 24 hours — “The Katrina of tornado outbreaks“ — I examined the climate/tornado link in great detail here, looking at the data, the literature, and expert analysis. That piece concluded:

1. When discussing extreme weather and climate, tornadoes should not be conflated with the other extreme weather events for which the connection is considerably more straightforward and better documented, including deluges, droughts, and heat waves.
2. Just because the tornado-warming link is more tenuous doesn’t mean that the subject of global warming should be avoided entirely when talking about tornadoes.

Early March 2012 saw what was likely “the most prolific five-day period of tornado activity on record for so early in the year,” as meteorologist Dr. Jeff Masters put it.

Then we had an unusually long “tornado drought” from May 2012 to April 2013, which has now come to a stunning end, punctuated by the devastating Moore, Oklahoma tornado yesterday:

A massive, mile-wide supercell tornado ripped through the suburbs of Oklahoma City, destroying homes, schools and other buildings. The tornado was on the ground for some 40 minutes, according to the National Weather Service (NWS), and police reported that an occupied elementary school was in the path of the cyclone. Early estimates had winds on the ground near 200 mph, which would have made the cyclone an F4 or higher. Witnesses said the damage was like something out of an atomic bomb strike, and there are at least 24 people dead, including many young children, with a toll that could eventually be far higher.

Masters says “the Moore tornado likely to be one of the five most damaging tornadoes in history,” which is particularly tragic because Moore had “previously experienced the 4th costliest tornado in world history, the notorious May 3, 1999 Bridgecreek-Moore EF-5 tornado.”

You can donate to the American Red Cross disaster relief here.

Below is an extended review of the scientific literature along with some analyses from this year and last year by leading experts.

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It would be good news if the climate’s sensitivity to carbon pollution were on the low side. No, that wouldn’t save us from catastrophic global warming — 7°F warming or higher — if we stay anywhere near our current emissions path (as I explain here).

But a low sensitivity would mean that aggressive action to reduce CO2 emissions starting now would have a modestly higher chance of keeping total warming below 4°F and averting the worst impacts. That’s the point of New Scientist‘s article, “A second chance to save the climate” on a new sensitivity study in Nature Geoscience:

“If we are lucky and the climate sensitivity is at the low end, and we have a strong agreement in 2015, then I think we stand a chance to limit climate change to 2 °C,” says Corinne Le Quéré of the Tyndall Centre for Climate Change Research in Norwich, UK. “But there’s a lot of ifs.”

If this new study is accurate, then near-term surface warming might be less than expected. But as the lead author Oxford’s Dr. Alexander Otto told the BBC, “We would all like climate sensitivity to be lower but it isn’t.”

The researchers say the difference between the lower short-term estimate and the more consistent long-term picture can be explained by the fact that the heat from the last decade has been absorbed into and is being stored by the world’s oceans.

Recent studies make clear the ocean is warming quite fast, as (see “Global Warming Has Accelerated In Past 15 Years, New Study Of Oceans Confirms” and here). If, as many climatologists believe, some of that ocean heat is released to the surface in the next decade or two, that would reverse the recent slowdown in the rate of surface warming.

Also, many other recent studies find that the climate is more sensitive than we expected:

• Last Time CO2 Levels Hit 400 Parts Per Million The Arctic Was 14°F Warmer!
• Observations Support Predictions Of Extreme Warming And Worse Droughts This Century

Indeed, the new study does little to eliminate the confusion about sensitivity. The media continue to conflate and confuse climate sensitivity with how much warming will we subject our children and countless future generations to (see here and below).

Another related source of confusion is conflating “climate sensitivity” — which generally refers to the change in the global surface temperatures (absent major feedbacks) — with how sensitive the climate itself is to changes in temperature.

For instance, our climate models wildly underestimate what’s happening in the Arctic right now:

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Rep. Glenn Gruenhagen

On Wednesday night, Minnesota State Representative Glenn Gruenhagen (R-Glencoe) took to the House floor to talk about climate change and renewable energy.

Using sources such as the Conservative Political Action Conference (CPAC), Gruenhagen told his colleagues that climate change is a “complete United Nations fraud and lie…. The latest facts from CPAC show that in the last sixteen years there’s been no global warming.”

While it is common practice among climate skeptics to claim that the Earth is no longer warming, the fact is global temperatures are rising. 2010 was the hottest year on record and every year of the 2000s was warmer than 1990s average. Over 30 million people were displaced by climate-related extreme weather events in 2012, and it is increasingly likely millions more will be displaced in the near future.

Watch the speech here, courtesy of theuptake.org:

Gruenhagen made his speech the same day a new survey of over 12,000 peer-reviewed climate science papers found a 97 percent consensus that global warming is happening and humans are the cause and just a few days after it was reported that atmospheric C02 levels reached 400 parts per million (ppm) for the first time in human existence

Indeed, Minnesota residents are feeling the very real impacts of climate change. The MinnPost reports that three 1,000 year floods have occurred in the state in the last eight years as a result of shifts in rainfall patterns. Extreme drought is occurring not just in Minnesota but almost every state, and climate change is having cumulative stress on the Great Lakes. Rising levels of water vapor in the warming atmosphere are spiking heat indexes and associated health warnings.
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Matt Kasper is the Special Assistant for Energy Policy at the Center for American Progress.

China's Loess Plateau

A UCLA news release reveals yet another key part of the world is far more sensitive to climate change forcing than the models had suggested.

Temperatures in central China are 10 to 14 degrees Fahrenheit hotter today than they were 20,000 years ago, during the last ice age, UCLA researchers report — an increase two to four times greater than many scientists previously thought.

The findings, published today in the early online edition of the journal Proceedings of the National Academy of Sciences, could help researchers develop more accurate models of past climate change and better predict such changes in the future.

“Previously, we could only infer temperature on land through changes in climate archives like tree rings or pollen over time,” said lead author Robert Eagle, a UCLA researcher in the department of Earth and space sciences. “This is the first time that temperature has been determined accurately on land at the time of the last ice age.”

To make their temperature measurements, the scientists used a technique known as clumped isotope thermometry, which detects subtle atomic differences in calcium carbonate, a compound commonly found in rocks, snail shells and wind-blown dust deposits known as loess. The method is the most accurate land-based temperature-determination tool available today.

“We can now tell what temperatures were on land 20,000 years ago with more accuracy than was ever previously possible,” said senior author Aradhna Tripati, a UCLA assistant professor in the department of Earth and space sciences and the department of atmospheric and oceanic sciences.

Tripati and Eagle chose to study the Loess Plateau in central China, a 250,000-square-mile agricultural region some 500 miles southwest of Beijing, because of its wide expanses of loess, the silty sediments that give the area its name and which contain deposits from the last ice age.

“We can calculate temperatures and reconstruct the chemistry of rainwater from the past ice age, then compare this to the present day climate in specific regions,” Eagle said. “We can then use this information to validate current climate models and study atmospheric processes.”

The researchers collected two unique ice age sample types from the Loess Plateau region: fossilized land-snail shells and soil deposits. While snails calcify quickly over just a few years, soil carbonates grow over longer time periods, ranging from a few hundred to thousands of years. Eagle and Tripati used clumped isotope thermometry to determine the temperature at which these samples formed roughly 20,000 years ago.

“One of the most important aspects of the study was showing that we could get the same result from such different types of carbonates,” said Tripati, who is also a member of UCLA’s Institute of the Environment and Sustainability. “Even though these materials integrate over very different time frames, they gave us the same result.”

Comparing the findings with climate models

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False balance is alive and well at even the best media outlets (see links below). Bloomberg news, famous for the post-Sandy cover story,“It’s Global Warming, Stupid,” now proves they can be the stupid ones, in a Monday piece on “Greenhouse Gases Hit Threshold Unseen in 3 Million Years”:

Happy Plants

“The Earth has had many-times-higher levels of CO2 in the past,” said Marc Morano, former spokesman for Republican Senator James Inhofe and executive editor of Climate Depot, a blog that posts articles skeptical of climate change. “Americans should welcome the 400 parts-per-million threshold. This means that plants are going to be happy, and this means that global-warming fearmongers are going to be proven wrong.”

Yes, “Happy Plants” is Bloomberg’s header. Plants will be so damn happy when it is 10° F warmer and a third of the arable land has been turned to dust bowl!

And yes, Bloomberg actually quoted Marc Morano, the Charlie Sheen of global warming, former denier-in-chief for Sen. James Inhofe (R-OIL) — “among the first reporters to write about the Swift Boat Veterans for Truth campaign.”

As Media Matters notes, you should know your news article is pushing false balance when you are quoting someone making the exact same argument as a “rock bottom” Wall Street Journal op-ed:

Marc Morano is not a scientist and has no scientific education. He is paid by an oil-industry funded organization to confuse the public about climate change, and has compared climate science to the Mayan calendar, Nostradamus, and medieval witchcraft. Moreover, his argument is laughable: by focusing on how carbon dioxide stimulates plant growth in a controlled environment, he ignores that our huge emissions of it and other greenhouse gases are warming up the planet, thereby increasing the risk of extreme rainfall and drought to the detriment of agriculture. A Wall Street Journal op-ed made the same argument on Thursday, leading to a deluge of condemnation.

So why is Bloomberg News not only featuring Morano, but giving his discredited argument equal weight to the extensive evidence presented by scientists?

Equally lame, Bloomberg trots out a long-debunked denier talking point:

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You can help crowd-fund an important scientific research trip — along with a videographer and journalist to cover it. Climate De-Crocker Peter Sinclair explains:

On April 21, 2013, the Dark Snow Project brought a bit of Greenland to Manhattan, to illustrate the importance of this summer’s planned expedition to sample Greenland ice. It kicked off the last leg of our historic citizen-science crowd funding campaign.

If this final fundraising push is successful, I’ll be traveling in June to the Greenland Ice sheet as part of a scientific expedition to investigate the steady darkening and increasing melt of that important ice sheet. Bill Mckibben will be coming along to write this up for Rolling Stone, as well.

Here is a video on the Dark Snow Project:

They are almost half-way to their $150,000 target. Let’s see if Climate Progress readers can take them over $100,000. Here’s how:

One, you can go to Darksnowproject.org, and make a donation at the bottom of the page. Two, you can text darksnow to 50555.

We have pushed atmospheric CO2 levels to 400 parts per million (ppm) for the first time in human existence.

At the same time, a truly remarkably set of paleoclimate data shows the climate is much more sensitive to CO2 than we thought. And that means returning as quickly as possible back to 350 ppm is a vastly more rational course of action for a non-suicidal civilization, than, say continuing our unrestrained march toward 600 ppm, then 800, and then 1000.

NOAA reported Friday that the daily mean concentration of CO2 in the air around Mauna Loa, Hawaii, surpassed 400 parts per million this week:

At the same time, a major new Science study of paleoclimate temperatures — based on ”the longest sediment core ever collected on land in the Arctic” – revealed what happened the last time we had similar CO2 levels:

“One of our major findings is that the Arctic was very warm in the Pliocene [~ 5.3 to 2.6 million years ago] when others have suggested atmospheric CO2 was very much like levels we see today. This could tell us where we are going in the near future. In other words, the Earth system response to small changes in carbon dioxide is bigger than suggested by earlier models,” the authors state.

Yes, contrary to one or two (misreported) models suggesting a climate sensitivity on the low side, this study joins the myriad analyses of data that find it is likely to prove on the high side. For instance, recent observations of relative humidity in the tropics and subtropics found that “Future warming likely to be on high side of climate projections,” according to a November paper in Science.

How sensitive is the climate to increases in CO2, according to this “absolutely new knowledge” of paleoclimate temperatures?

Another significant finding to emerge from this first continuous, high-resolution record of the Middle Pliocene is documentation of sustained warmth with summer temperatures of about 59 to 61 degrees F [15 to 16 degrees C], about 8 degrees C [14 F] warmer than today.

This period of Arctic warmth “coincides, in part with a long interval of 1.2 million years when the West Antarctic Ice sheet did not exist.” Indeed, sea levels during the mid-Pliocine were about 25 m [82 feet] higher than today!

It is worth noting that a 2009 analysis in Science found that when CO2 levels were this high 15 to 20 million years ago, it was 5° to 10°F warmer globally and seas were also 75 to 120 feet higher.

The risks of failing to sharply curtail carbon pollution are enormous if the climate sensitivity is on the low side (see “Memo To Media: ‘Climate Sensitivity’ Is NOT The Same As Projected Future Warming, World Faces 10°F Rise“). But the risks of inaction are beyond incalculable if climate sensitivity is in the middle end of the range, let alone the high end suggested by the paleoclimate data:

Science (1/11) study — On our current emissions path, CO2 levels in 2100 will hit levels last seen when the Earth was 29°F (16°C) hotter: Paleoclimate data suggests CO2 “may have at least twice the effect on global temperatures than currently projected by computer models”

As I explained in Nature online back in 2008 (here), once you factor in carbon-cycle feedbacks, even the uber-cautious Fourth Assessment report (AR4) of the IPCC makes clear we are headed toward 1000 ppm (the A1FI scenario). That conclusion has been supported by just about every major independent analysis, including a recent report by PricewaterhouseCoopers (see Study: We’re Headed To 11°F Warming And Even 7°F Requires “Nearly Quadrupling The Current Rate Of Decarbonisation“).

This new paper is just the latest to suggest the Arctic will warm much faster than the models have suggested. For instance, back in 2006, scientists analyzed deep marine sediments to understand the Paleocene Eocene thermal maximum, a brief period some 55 million years ago of “widespread, extreme climatic warming that was associated with massive atmospheric greenhouse gas input.” That Nature study (subs. req’d) found Arctic temperatures almost beyond imagination–above 23°C (74°F)–temperatures more than 18°F warmer than climate models had predicted when applied to this period. The three dozen authors conclude that existing climate models are missing crucial feedbacks that can significantly amplify polar warming.

Clearly our climate models don’t do a good job of explaining what’s happening in the Arctic right now:

Arctic sea ice is melting much, much faster than even the best climate models had projected (actual observations in red). The reason is most likely unmodeled amplifying feedbacks. The image (from Climate Crocks via Arctic Sea Ice Blog) comes from a 2007 GRL research paper by Stroeve et al.

And this underestimation of polar amplification in turn leads the authors of the new study — and many other scientists — to conclude that the climate’s overall sensitivity is on the high side. As the UK Guardian reports:

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On Friday, the City of New York allocated $294 million of Superstorm Sandy recovery funds for resiliency projects to respond to the threat of fossil-fueled climate change.

The announcement was part of the unveiling of NYC’s plan for $1.77 billion in Sandy recovery initiatives by Mayor Michael Bloomberg, Housing and Urban Development Secretary Shaun Donovan, and Sen. Charles Schumer (D-NY) at New York City Hall:

The City has set aside $294 million for resiliency investments to be detailed in a report issued by the Special Initiative for Rebuilding and Resiliency later this month.

“HUD’s approval of our comprehensive Action Plan enables us to take the next critical step toward recovery – launching the programs for home rebuilding and business assistance that will rejuvenate the neighborhoods Sandy hit hardest,” said Deputy Mayor for Operations Cas Holloway. “We’ll also take the first steps toward making the City more resilient to the impacts that we know climate change will bring.”

The sequester cuts reduced the planned budget for resilience from an original $327 million.

The New York City Special Initiative for Rebuilding and Resiliency (SIRR) was established by Bloomberg in November, 2012, with an explicit mission to address global warming:

When it comes to climate change, New York City has long been considered a leader in long-term sustainable planning, but Hurricane Sandy was a wake-up call to all New Yorkers.

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The Arctic is the fastest changing place on earth. The most obvious and important change is the staggering loss of sea ice (see “CryoSat-2 Confirms Sea Ice Volume Has Collapsed“).

In addition, “the Arctic marine waters are experiencing widespread and rapid ocean acidification,” a new study finds. This first-ever Arctic Ocean Acidification Assessment, commissioned by the Arctic Council’s Arctic Monitoring and Assessment Programme (AMAP), explains that the “primary driver of ocean acidification is uptake of carbon dioxide emitted to the atmosphere by human activities.”

We knew from a 2010 Nature Geoscience study that the oceans are now acidifying 10 times faster today than 55 million years ago when a mass extinction of marine species occurred. We are risking a marine biological meltdown “by end of century” as a 2010 Geological Society study put it.

As the lead author of a 2012 study on acidification in Science explained, “if industrial carbon emissions continue at the current pace, we may lose organisms we care about—coral reefs, oysters, salmon.”

Here is a video from AMAP on Arctic Ocean acidification:

The Key Findings of the AMAP study are here.

Related Posts:

• Bad Acid Trip: USGS Study Finds Humans Are Acidifying ‘The Air, Oceans, Freshwaters And Soils’
• The Great Oyster Crash and Why Ocean Acidification Is “A Ticking Time Bomb” for Both Marine Life and Humanity

Image by John Garrett

Part 1 took on a NY Times essay that pushed the myth “We already know it’s too late” to stop climate catastrophe. In fact, many recent studies have concluded that aggressive action now to curtail carbon pollution could keep us at the low end of warming, where impacts are far more manageable.

Here I’ll extend that discussion, while taking on a NYT Dot Earth post that pushes other dangerous myths, such as the notion climate change impacts are reversible on a timescale that matters to humans.

In his post, “An Earth Scientist Explores the Biggest Climate Threat: Fear,” NYT climate blogger Revkin introduces an extended comment from Peter Keleman this way:

Here’s a “Your Dot” contribution pushing back against apocalyptic depictions of the collision between humans and the climate system — written by Peter B. Kelemen, the Arthur D. Storke Professor and vice chair in the Department of Earth and Environmental Sciences at Columbia University. Kelemen has done a lot of interesting work on possible ways to capture carbon dioxide from air (none being easy or cheap):

Not quite.

What Keleman wrote is a pushback against “apocalyptic depictions of the collision between humans and the climate system” that say it is too damn late to do anything (depictions which, as I’ve discussed, are relatively rare and generally debunked when they do appear).

Keleman begins:

Fear Itself

“We already know it is too late to reverse the planet’s transformation, and we know what is going to happen next – superstorms, super-droughts, super-pandemics, massive population displacement, water scarcity, desertification and all the rest. Massive destruction, displacement and despair. Our worst fears are already upon us. The reality is far worse than anyone has imagined.”

These phrases are distilled from “Writing [at] the End,” an essay by Nathaniel Rich in Sunday’s New York Times Book Review. They capture its doomsday ethos, and its breathtaking certainty. Rich, a novelist, is sure he knows the causes of our present ills, and the nature of the near future. He probably feels that he learned this from the 98 percent of climate scientists who – famously – agree on some things. I am part of that community; we agree that human greenhouse gas emissions are having a huge, negative effect on global climate. But I don’t agree with Nathaniel Rich.

Well first off, as anyone can easily see by checking the original, these phrases “distilled” from the Rich essay are not in order, and the second and fourth sentences are completely out of context.

“Massive destruction, displacement and despair” doesn’t refer to “what is going to happen next” — it comes from the essay’s first paragraph and applies to the  aftermath of hurricane Sandy (and the aftermath of Rich’s fictional hurricane Tammy in his novel). The sentence “The reality is far worse than anyone has imagined” applies to Ian McEwan’s novel Solar, and what Rich apparently means is that our current reality is far worse than we imagined. That is hardly an unreasonable opinion to have given the bark beetle devastation, the loss of Arctic ice and apparent its impact on extreme weather, the accelerating disintegration of both the Greenland and Antarctic ice sheets — to name but a few realities far worse than were imagined even a decade ago.

Second, Rich is pretty clearly writing a literary, not scientific, essay. He is a novelist writing an essay about dystopian fiction and how it is having trouble keeping up with what’s actually happening in the real world. It is strange to say the least to treat this as if it were some sort of science treatise.

Third, we know where Rich “learned this from” because he tells us! It’s not “from the 98 percent of climate scientists” but rather from “nonfiction polemics” like Overheated” and “Hot” — neither of which, I might add, are written by climate scientists.

Fourth, not to nitpick or anything, but Keleman isn’t really a climate scientist, at least in the classic sense that his comments would imply — he is a (distinguished) geochemist who mostly works on geochemisty, rather than someone who has published peer-reviewed articles on, say, projected climate impacts.

I mention this only because Keleman’s next paragraph pushes the tired myth that some large number of climate scientists (and others) are exaggerating climate impacts to get grants and publicity:

Apocalyptic warnings sell newspapers, power Web sites, and are surprisingly good for marketing. Beyond the media, in the sciences and social sciences, if your research predicts a scary outcome, your name gets in the news, your grants get funded, and you feel like Paul Revere (though you might be Chicken Little). It’s a heady experience.

No, no, and no.

If the first sentence were actually true then you’d expect climate coverage would be soaring in a desperate effort by the newspaper business to stave off its ongoing collapse. Instead, of course, media coverage of climate change has itself collapsed in the past several years (see here and here) — and what little there is generally ain’t apocalyptic.

Yes, it’s true, Climate Progress is probably the most widely read climate blog, but then we do not do the kind of unjustified “it’s hopeless” messaging Keleman disdains. Indeed, we’ve criticized the very few who do — or, rather, who did, in the case of James Lovelock.

Moreover, while it is a common trope that scary research gets your name in the news, that is also rather demonstrably not the case. To the extent that the media is paying attention at all, it would much rather run a (misleading) story on the occasional contrarian finding of a somewhat low climate sensitivity than a piece on the 95% of scientific studies published since 2007 that suggest things will be worse than we thought.

Ironically, climate scientists are as likely to be attacked as exaggerators (or as “Chicken Little,” for that matter) for reporting the increasingly dire situation we face as they are to be celebrated. Go figure.

Given Keleman’s disdain for those who supposedly get grants funded for predicting a “scary outcome,” it seems odd that he would be working on “possible ways to capture carbon dioxide from air (none being easy or cheap).” Unless inaction on CO2 emissions were to lead to a ”scary outcome,” why would anyone bother with expensive, difficult measures to capture CO2???

It is, in fact, the grim reality of our predicament that justifies such work — and the recent scientific literature makes it painfully clear (see a review of over 50 recent studies here). That’s why the normally staid folks at the World Bank and PricewaterhouseCoopers and the International Energy Agency are in a panic.

Keleman continues:

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