December 20, 2010 — andyextance

A year’s worth of interviews with scientists comes down to this: a tussle between different styles of expression. Is it better to be detailed or brief? Is it better to discuss the causes, or the effects? That’s what this, the final round of Simple Climate polls, is asking you, the reader.

One of the aims of my blog is to produce a single, simple, explanation of climate change. Over the past four weeks I’ve run four polls that have summarised all the explanations of climate change that scientists have given me this year, and you can still visit them if ever you need a refresher. By voting on them readers have selected their favourite in each of the four different categories of explanation I divided them into.

The most popular in each category is listed below: In fact there are five explanations, as the poll of explanations of the effects of change was tied. Now you have until the end of the year to choose the most popular of all the explanations I’ve been given. Vote now in the poll below these explanations, and use the commenting tools below that to discuss them. Happy voting!

Most popular direct explanation of the physics underlying climate change:



Kevin Trenberth, head of the Climate Analysis Section, National Center for Atmospheric Research, Boulder, US:

The Earth is habitable because of a natural greenhouse effect brought about mainly by water vapor (60%) and carbon dioxide (26%). Otherwise its average temperature would be below zero Fahrenheit. Humans are altering the composition of the atmosphere, mainly by burning fossil fuels. As a result carbon dioxide has gone up over 35% since pre-industrial times and over half of that is since 1970. This changes the greenhouse effect and traps radiation that would otherwise escape to space, producing warming. The warming is manifested in many ways, not just increasing surface temperatures, but also melting ice, and changing the hydrological cycle and thus rainfall. Since 1970 the effects are large enough to be outside the bounds of natural variability for global mean temperatures, but global warming does not mean inexorable increases in temperature year after year owing to natural variability.

Most popular one-line and metaphorical explanation:

George Wang, biologist, Max Planck Institute for Developmental Biology, Tübingen, Germany:

Global average temperatures are increasing due to man-made changes in the composition of our atmosphere.

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Most popular attempt to explain climate change at a personal level:

Brian Chase, physical geographer, Institute of Evolutionary Sciences, Montpellier, France:

I wish I, or anyone, could, but I personally don’t believe that a simple explanation of ‘climate change’ presently exists. Many people who suggest otherwise are, while often with good intentions, trying to sell something.

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Joint most popular description of the effects of change:

Barry Sinervo, evolutionary biologist, University of California, Santa Cruz, US

All animals are adapted to critical thermal limits from millions of years of evolution and they simply cannot adapt fast enough to current rates of climate change. They live in specific thermal habitats to which they are adapted. Near some parts of their range it is too hot – that is what we call the thermal limit of a species. These thermal limits are moving rapidly and squeezing lizards to the limit.

Too many individuals have to die to accomplish the process of adaptation. Adaptation is based on natural selection, which involves survival of the most fit – i.e. high body temperature in the case of climate warming – and selective death of others – e.g. low body temperature forms. Right now too many individuals are dying selective deaths to sustain a positive value of population replacement. In many areas this is driving populations into negative values of population replacement which pushes them to lower and lower numbers, given that climate warming is relentless, eventually culminating in extinction.

Joint most popular description of the effects of change:

Bill Morris, biologist, Duke University, Durham, US:

With more greenhouse gases in the atmosphere, we will have a warmer world with altered patterns of precipitation. Both of these changes will alter where each species can live.