Simple Climate poll part 2: One-liners and metaphors

Is a short, direct, or longer, metaphorical, explanation better for understanding how changes in the atmosphere are warming the planet? Credit: Max Planck Institute for Meteorology / Stevens

Do you understand climate change better if you think of the Earth putting on a jumper, or if how it works is described to you in as few words as possible? Simple Climate has been talking to researchers this year to understand the science of climate change and its impacts, and in the process get simple explanations from these experts. Last week I recapped seven direct explanations of the physics underlying climate change and gave readers the chance to vote for their favourite and comment on them. While you can still vote there, this week I’m recapping six more concise or picturesque efforts. Read them, and then feel free to vote for your favourite and/or comment at the end to help me with one of the aims of my blog – producing a single, simple explanation of climate change. Happy voting!

Methane release undermines CO2 emissions slowdown

Atmospheric radiative forcing - a measure of the degree of warming Earth experiences - of all long-lived greenhouse gases and the 2009 update of the US National Oceanic and Atmospheric Administration Annual Greenhouse Gas Index (AGGI), which shows radiative forcing has increased 27.5% since 1990. Credit: World Meteorological Organisation

The amount of greenhouse gases in the atmosphere reached the highest level recorded since pre-industrial times in 2009, despite a fall in CO2 emissions during the year, scientists have underlined this week.

Writing in Nature Geoscience on Sunday, a group of UK, US and Australian scientists found that global CO2 emissions from burning fossil fuel in 2009 were 1.3 percent below the record 2008 figures. However, the World Meteorological Organization (WMO) on Wednesday underlined that the overall amount of “radiative forcing” from greenhouse gases – a measure of the warming energy that they contribute – actually rose by 1 percent in 2009. The WMO notes that reduced growth rates for concentrations of greenhouses gases like CO2 and nitrous oxide last year were accompanied by more rapid growth for methane.

Pick the best Simple Climate change explanation

The radiation that reaches Earth from space is one factor that shapes our climate. Credit: Danish National Space Center

So, just what is the best simple explanation of climate change? Answering that question was the aim of the one-year quest I set myself in January when I set up this blog. Since then, scientists from around the world have helped me try and find an answer. While not all of them have offered their own explanations, 26 have. They’re all great in different ways, so I had difficulty imagining how to refine them into a single version. The solution to this problem, I decided, is to enlist your help in choosing which of the different explanations is best.

Between here and the end of the year I will be recapping these explanations, and running a series of polls, so Simple Climate readers can vote to choose the best one. Among the explanations there are a number of different approaches. Most scientists address the physics underlying climate change, either metaphorically or directly, with the direct explanations split between one-liners and longer versions. Many, however, explain climate change in terms of its effects, and some give a more personal or political explanation.

This week’s poll features the longer physical explanations, then next week will be one-liners and metaphorical physical explanations. The effects and personal explanations will then be included in votes over the following two weeks. Then, the winner of each of these will compete against each other in the final poll, over the final 10 days of 2010. In parallel with these polls, I’ll use my midweek blog entries to summarise what else I’ve learnt this year, beyond the explanations.

Extra satellite records settle tropospheric warming row

The latest NOAA-N Prime satellite which carries instruments for imaging and measuring the Earth's atmosphere, its surface and cloud cover, including Earth radiation, atmospheric ozone, aerosol distribution, sea surface temperature, and vertical temperature and water profiles in the troposphere and stratosphere. Credit: Lockheed Martin Space Systems

After several hundred papers, two expert assessments, and numerous political hearings, conflicts in climate science posed by high-profile claims that there is no warming trend near Earth’s surface have finally been resolved. The controversy surrounds the first measurements of temperatures in the troposphere – the segment of the atmosphere closest to Earth’s surface – taken by satellite. In 1990, John Christy from the University of Alabama, Hunstville (UAH), and Roy Spencer at the Marshall Space Flight Center, also in Huntsville published their analysis of the first decade of measurements. They found that there has been no clear temperature rise over the prior decade, a serious disagreement with the increases seen in measurements made at the surface.

Now US and UK scientists have reviewed the research done in the 20 years done since that paper and another 20 years before it, and found that the disagreement has been accounted for. In a Wiley Interdisciplinary Reviews – Climate Change paper published on Monday, the team says that while it is now clear that warming is happening, debates remain on exactly how rapidly. Additional collections of data that have been established more recently than the initial research played an important part in clearing up the controversy. “There is an old saying that a person with one watch always knows what time it is, but with two watches one is never sure,” said Thomas Peterson, lead scientist at the US National Oceanic and Atmospheric Administration’s National Climatic Data Center. “The controversy started with the production of the first upper-air temperature ‘watch’ in 1990, and it was only later when multiple additional ‘watches’ were made by different ‘manufacturers’ that we learned that they were each a few minutes off. Although researchers all agree the temperature is increasing, they disagree how much.”

When climate becomes a problem too far

University of New South Wales associate psychology professor Ben Newell. Credit: University of New South Wales

If you can face the sheer volume of evidence for global warming and not become too numbed and overwhelmed to act, you are probably quite an unusual person. That’s one warning offered by University of New South Wales psychologist Ben Newell, who published research back in August discussing how we think about climate change. “We can only worry about a limited set of issues, Newell emphasised in the Bulletin of the American Meteorological Society. That means that when people like me try and communicate the evidence, we must be careful how we do it.

Research at the Centre for Environmental Decision Making at Columbia University has shown that “people remember more and report more willingness to take action when shown vivid imagery, like receding glaciers, than when just given facts and figures,” Newell told Simple Climate. “I think this emphasises the need to engage people with images that they can relate to and easily understand. However, we should avoid inducing ‘despair’ by showing “Day After Tomorrow” type catastrophes. A good method might be to show images of real impacts on local regions that have changed over a specified time period rather than artists’ impressions of what could be.” Interestingly, these findings are also shared by University of California, Berkeley, researchers in the journal Psychological Science set to be published in January.

This is just one small element of the wide range of insights that Newell’s work provides, another aspect of which has already been covered on this blog, and which are summarised overall in the following video:

Air-stilling temperatures create heat, wind power threats

Average observed sea surface temperature (black) and convection threshold (blue) rose together in the last 30 years. Credit: University of Hawaiʻi at Mānoa

How air circulates around our planet is being affected by climate change in ways that will pose real challenges for humanity. That’s according to two studies highlighted this week, one looking at convection – the movement of air vertically through the atmosphere – and one at Earth’s surface winds. The first brings good news on how often hurricanes will happen, but more worrying news on the combination of temperature and humidity humans must endure. The second underlines that in order to get the most out of wind power, turbines must be installed before temperatures rise too greatly.

Hurricanes and tropical ocean thunderstorms are aspects of the atmospheric convection that tends to happen when the sea surface passes a certain temperature limit. Writing in Nature Geoscience on Sunday, University of Hawaiʻi at Mānoa’s Nat Johnson and Shang-Ping Xie found that this threshold has been rising in parallel with the world’s average sea surface temperature. “The correspondence between the two time series is rather remarkable,” said UH Mānoa researcher Johnson. “The convective threshold and average sea surface temperatures are so closely linked because of their relation with temperatures in the atmosphere extending several miles above the surface.”

Climate change shifts organisms in space and time

Duke University Biologist Bill Morris. Credit: Duke University

As our climate changes, we might expect to see some familiar plants and animals in our local environment replaced by new ones. That’s according to Bill Morris from Duke University in Durham, North Carolina, who recently published work studying shifts in where mountain plants live in top science journal Nature. “Species will likely be found in different places than where they are found now, creating new combinations that did not interact in the recent past,” he told Simple Climate. “What the consequences of these new interactions will be are hard to predict, because it is difficult to study interactions that don’t currently exist.”

Together with Daniel Doak at the University of Wyoming, Morris studied two tundra plant species whose habitat extends south from the Arctic. Higher global temperatures are expected to make conditions for the moss campion and alpine bistort better at the northern end of their geographical ranges. By contrast, at the southern end higher temperatures might be expected cause the plants to decline. Consequently their southern range limit should move northwards, but Morris and Doak found that in fact this had not happened – at least not yet.

Morris explained that the question of whether species’ ranges are spreading, or if it’s more common for the range to stay the same size, but move, remains unanswered. “We have much better evidence that species such as butterflies and birds are shifting toward the poles and to higher elevations, because these species are more often noticed by amateur naturalists, and because they likely move faster than do plants,” he said. “But we do know that many plants in Europe, where historical information about plant distributions is better, have moved to higher elevations over the last century.”

Prehistoric CO2 double-up gives warming data

Electron microscopic picture of microfossils found in drill cores of sediments dating back 40 million years. By studying the remains of such marine plankton - and particularly compounds they produce called alkenones - scientists gain an accurate perspective of past climate change. Earlier, members of the same research team showed that the Arctic Ocean was colonized by similar types of tropical plankton. Scale bar is 20 millimetres, or 0.02 millimetres. Credit: Appy Sluijs

The first direct evidence supporting the idea that a recently-discovered period of global warming, one of the hottest in Earth’s history, was caused by CO2 has been published this week. Before the Middle Eocene Climatic Optimum (MECO), which occurred 40 million years ago, temperatures were much higher than today, but steadily falling. However, the MECO was a 400,000 year warming reversal of this trend. Researchers from the Netherlands and UK have now shown that it was accompanied by at least a doubling in atmospheric CO2 levels. Utrecht Univesity’s Peter Bijl and his colleagues also provide cautious estimates for just how much warming can be expected from adding CO2 in top journal Science this week.

Scientists already suspected that the approximately 4°C MECO temperature rise was caused by CO2. “There are only three ways to cause a large and lasting increase in Earth’s average surface temperature,” pointed out Paul Pearson from Cardiff University, UK, who was not involved in the study. “Turn up the heat from the Sun, reflect less sunlight back into space, or trap more heat in the atmosphere.” The heat from the Sun is relatively stable, Pearson comments in a separate article in this week’s Science giving his perspective on the research. Changes in the Earth’s reflectivity due to melting ice tend to happen after climate change has already begun, making greenhouse gases that trap heat around the Earth a likely culprit.

Extracting urine in the name of climate research

Brian Chase, of the Institute of Evolutionary Sciences in Montpellier, France, principal investigator on the project "HYRAX". Credit: Institute of Evolutionary Sciences

The deposits collected in a distant relative of the elephant’s communal toilets are challenging some long-held beliefs about the climate of the Earth’s dry regions. That’s not to equate existing science with animal dung, or even cite some quasi-mystical prediction method. Instead, Brian Chase from the Institute of Evolutionary Sciences in Montpellier, France, and his colleagues commenced a five-year European funded project on Monday to study the chemical composition of the toilets or “middens” of the rock hyrax.

The possibility of using middens for scientific analysis comes because populations of hyraxes use the same ones for thousands of years. However, despite being part of the same family as the elephant, hyraxes look more like guinea pigs, and live in locations that present already unusual-sounding research with even more improbable challenges. “With few exceptions middens are found high on cliffs, often under large overhangs, which makes access particularly difficult,” Chase explains. “Add to this an assortment of power tools, loose rock, poor protection, and the logistics of rigging a system that will allow you to safely remove and lower a 50 kg block of dense, but surprisingly fragile urine, and it is fair to say that the entire enterprise takes a rather special skill-set.”