Jeffrey Kiehl is a senior scientist in the Climate Change Research section at the National Center for Atmospheric Research in Boulder, Colorado. The Forum committee tries to include a speaker from a local organization at Forum; this year that speaker happens to be talking about a topic that’s been much in the news lately.
History of climate change science
Joseph Fourier (the same mathematician who gave us the Fourier transform) asked: What determines the temperature of Earth? In papers published in the 1820s, he hypothesized that the atmosphere must be blocking the escape of some of the reflected heat from the Sun; otherwise the earth’s surface temperature would calculate as near freezing. In the 1860s, John Tyndall built on Fourier’s work with experiments to determine which gases absorb heat rather than letting the heat out of the atmosphere. One of these gases was carbon dioxide. Svante Arrhenius noted that the Earth would warm by 4 degrees Centigrade with a doubling of the carbon dioxide in the atmosphere due to the amounts released by then-current industry (1890s).
Not until the 1950s did Dave Keeling at La Jolla put together a lab to measure the carbon dioxide in the atmosphere. That regular measurement has continued to this day and the carbon dioxide is continuing to increase over time. There’s a regular up-and-down line in the graph of levels of carbon dioxide which Jeffrey calls “the breath” of Earth. During the summertime, the level of carbon dioxide lowers because plants absorb carbon dioxide. During the winter, when deciduous plants drop their leaves, carbon dioxide levels increase.
How has the climate changed?
Rainfall increase in intensity
Snow cover and sea ice decrease
Ocean heat and acidity increase (most particularly has effect on the ability of the smallest sea organisms to grow shells and survive)
Sea level rises, not due to polar ice cap melt, but due to increase in heat of the ocean and to melting ice from land masses draining into the ocean (if Greenland and Antarctica both had all their ice melted off, this is projected to increase sea level up to 250 feet)
Observed temperature data for last approximately 100 years used to generate simulations into the past as well as the future
Previous large increases in heat and carbon dioxide in the atmosphere caused large extinctions of both sea and land species about 250 million years ago
Scientists still do not understand why measurements of e.g. Greenland ice melt are accelerating relative to what their models would have projected
How will the climate change?
Trying to extrapolate from current trends: Why does just a 4 degree temperature change make a difference? 100 million years ago the planet was approximately 10 degrees C higher than it is now. We will take the Earth back to a climate it hasn’t had in millions of years within the space of 100 years. This will have tremendous consequences for life because evolution does not normally operate in timeframes of a century.
Running simulations against previous observed data into the past shows a good correspondence between projected and observed data. However, a model projected a sudden collapse of polar sea ice conditions in about 2030 — but a paper that just came out shows the actual observed level has reached the 2030 projection now. Scientists are concerned there is some other factor they don’t know about that is also having an effect beyond what their current projections show.
He displayed a chart projecting US southwest water availability — lower and lower in the next century, although it wasn’t clear to me what the direct relationship is between temperature and water availability. He did show a map indicating the temperature changes over time are not evenly spread around the world, but rather concentrated regionally over areas like Greenland, the US Midwest, and northern Africa.
Sea surface warming leads to more severe hurricanes and to sea water impacts onto freshwater supplies in Pacific islands. Polar bears are expected to be extinct within 40 years.
How are we involved in the change?
The amount of resources required to support everyone on the planet at the level of US society would require eight planets Earth. The amount of carbon emissions from China has just started to exceed the amount from the US. That’s not a high amount per person, but the direction of the Chinese economy and society is towards the per-person level of the US.
- Growth in population
- Growth in demand for energy
- Changes in technology
- Changes in consumption
How to communicate information to the public?
Switching gears from the scientific to the social. It is very difficult to translate the information into a form that’s “digestible” by the public or politicians; “you have to find the right language.” This reminds me of a book I read recently on the communication issues between geeks and suits (technologists and management).
How the public values the environment:
Utilitarian value (what nature can do for me)
Intrinsic value (inherent value in nature independent of us)
Public surveys have indicated enormous (near 90%) of US population agrees with reducing emissions and Kyoto Protocol but very little (below 20%) support a gas tax. Despite apparent support for “them” to change, there’s less willingness for “me” to change — although Toyota is making lots of money on hybrids and Ford is losing (no-pain solutions do work).
What is the role of affect in conveying the message? Information by itself isn’t enough. Information is received in a context of other social factors. Scientific information, particularly, is generally shared in language that doesn’t have affect laden metaphors. If a message is transmitted with affect, there’s a tendency to defend against depressing news, taking forms like – denial – numbing – wishful thinking – wishing for a technological fix. Information is not enough to change attitudes.
Without deep reflection, we have taken on the story of endings, assumed the story of extinction … We need new stories … a new narrative that would imagine another way …” — Linda Hogan
Q. What are the differences in emissions in western Europe vs elsewhere? They are staying level
A. Changes in technology, e.g., much of France is nuclear
Q. And the big drop in emissions in Russia and former Soviet states?
A. Collapse of USSR