With all the attention surrounding carbon dioxide these days, it is easy to forget that there are a number of other important natural and human-driven factors (”forcings” in climate circles) that influence Earth’s climate.
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With all the attention surrounding carbon dioxide these days, it is easy to forget that there are a number of other important natural and human-driven factors (”forcings” in climate circles) that influence Earth’s climate.
An argument frequently used by those skeptical of the role of anthropogenic greenhouse gases in modern temperature increases is that warming is caused by the Sun.
At first glance, it seems to make intuitive sense: the Sun is a massive nuclear fusion reactor a million times larger than Earth, it is responsible for almost all the energy reaching our plant, and in the past few decades scientists have learned that solar activity varies significantly over time. Surely it must have a larger impact on our changing climate than a gas that comprises only a small fraction of our atmosphere?
Measuring Earth’s temperature is no easy task.
Four different groups produce temperature records that attempt to compile a single global mean surface temperature: NASA’s GISStemp, the Hadley Center’s HadCRU, Remote Sensing Systems’ RSS, and the University of Alabama, Huntsville’s UAH.
Among the most iconic image of Al Gore’s “An Inconvenient Truth” was that of coastlines and cities disappearing beneath rising seas.
Sea level rise is certainly one of the more worrisome impacts of climate change, but the film’s disregard of the time scales involved in sea level rise may have led some to think that sea level rise on the order of 20 feet is probable in this century. Scientists cannot completely rule out such rapid sea level rise, but the general sense in the climate science community is that a lower but still worrying degree of sea level rise is more likely.
Broadcast meteorologists do not have the best of reputations for predictive accuracy. Audiences are particularly good at remembering - and at pointing the finger - when they’re wrong. Few heap praise when their forecasts turn out to have been accurate.
So the rainy day expected tomorrow sometimes turns out to be sunny, and projections more than a week away are usually offered - and taken - with the proverbial grain of salt.
Water vapor is one of the most important elements of the climate system. A greenhouse gas, like carbon dioxide, it represents around 80 percent of total greenhouse gas mass in the atmosphere and 90 percent of greenhouse gas volume.
Water vapor and clouds account for 66 to 85 percent of the greenhouse effect, compared to a range of 9 to 26 percent for CO2. So why all the attention on carbon dioxide and its ilk? Is water vapor the real culprit causing global warming?
“Global temperatures have not increased since 1998.”
That point has been a common argument among climate skeptic communities in the blogosphere for the past few years. It gained prominence recently in an article in the New Statesman by David Whitehouse, a journalist and former BBC science correspondent.
Few climate change topics arouse more passion than the seemingly dry field of climate modeling.
Critics thunder that the models contain a “large element of subjectivity” with parameters “tweaked by those who operate the models” to achieve results that conform to scientists’ preconceptions. Some seem to think that these models simply represent a grandiose exercise in curve fitting, forecasting future climate based on the trend in temperatures over the past few decades.
Journalists covering the climate change issue for any period of time quickly run across arguments that the big concern just a few decades back had involved global cooling and not global warming.
They will do well to step back and look hard at those claims to see if they really hold up.
A fundamental misconception about the role that carbon dioxide plays in glacial transitions has helped fuel the argument that the lag time between temperature and CO2 in the paleoclimate record casts doubt on carbon dioxide as an important greenhouse gas.