As I was researching some of the comments on a previous post, here are some interesting items that I found:

1. C02 has historically lagged temperature, a fact that is often cited by global warming skeptics.

Temperature and CO2 are difficult to measure and compare. The time resolution is low, and while C02 is an atmospheric gas with a more global nature, temperature is always relatively local. Tom Rees explains this and gives links to data that you can review.

RealClimate explains that while it is true that CO2 lags temperature, this does not affect the global warming theory. The CO2 amplifies the temperature rise. So the concern is not that the increased CO2 we are creating today caused the rise, but that it will continue to amplify it.

2. The best explanations so far regarding why global warming is human caused:

RealClimate gives an explanation based on the measurement of carbon isotopes.

Ecobridge describes outputs of human activity that cause carbon dioxide and greenhouse gas.

Here’s what NASA has to say,

Climatologists (scientists who study climate) have analyzed the global warming that has occurred since the late 1800’s. A majority of climatologists have concluded that human activities are responsible for most of the warming. Human activities contribute to global warming by enhancing Earth’s natural greenhouse effect. The greenhouse effect warms Earth’s surface through a complex process involving sunlight, gases, and particles in the atmosphere. Gases that trap heat in the atmosphere are known as greenhouse gases.

The main human activities that contribute to global warming are the burning of fossil fuels (coal, oil, and natural gas) and the clearing of land. Most of the burning occurs in automobiles, in factories, and in electric power plants that provide energy for houses and office buildings. The burning of fossil fuels creates carbon dioxide, whose chemical formula is CO2. CO2 is a greenhouse gas that slows the escape of heat into space. Trees and other plants remove CO2 from the air during photosynthesis, the process they use to produce food. The clearing of land contributes to the buildup of CO2 by reducing the rate at which the gas is removed from the atmosphere or by the decomposition of dead vegetation.

A small number of scientists argue that the increase in greenhouse gases has not made a measurable difference in the temperature. They say that natural processes could have caused global warming. Those processes include increases in the energy emitted (given off) by the sun. But the vast majority of climatologists believe that increases in the sun’s energy have contributed only slightly to recent warming.

Finally, see the “Causes of Change” in the IPCC Fourth Assessment Report, as well as these global warming and climate change policy research sites:

National Oceanic and Atmospheric Administration.

NASA

While perusing the arguments on global warming, I happened across an article by Lorne Gunter that claims that “30 years of warmer temperatures go poof.” The article asserts that because recent global temperature anomalies went down to around the 0 mark, the temperature rise claimed by global warming researchers has been erased and all the global warming concerns have been much ado about nothing. To support this claim, Mr. Gunter uses this graph of this data from UAH:

Global Temperature with Incorrect Trend Line

The graph shows a “Global trend line” through the data, but this trend line is incorrectly drawn. See the graph below, made from the same data set:

Global Temperature with 100-Month Moving Average

In this second graph, a couple of things are clear. First, a correctly drawn trend line (in this case a 100-month moving average) shows a flattening but no significant decline. Second, the data in the second graph goes a few months further into 2008, where the temperature anomaly as risen, thus “regaining” about 20 years of the supposed 30 that were lost. The fallacy of the claim is thus clear: The temperature anomalies move in fairly wide swings. What is important is the rising mean temperature anomaly, not what the level is at any given month.

Mr. Gunter, unfortunately, is widely known for his outlandish claims. For a wonderfully detailed and well-linked analysis of other errors in the aforementioned Gunter article, see this greenfyre post.

Despite what seems to be an ironclad case for global warming and the assumption that it is human caused , there is still considerable debate in the media. If we are going to create appropriate public policy to deal with climate change, then we have to keep from being diverted by the fallacious arguments. Unfortunately, there is a lot of phooey out there perpetuated by people who cite scientists and who claim to be scientists. I’m not sure if these people are just misinformed or working on behalf of a hidden agenda, but we can filter them out by keeping aware of the essential situation.

The fundamental proposition goes like this:

1. For about the last 100 years, the Co2 level has been rising at an unprecedented rate. According to the Woods Hole Research Center,

Suddenly in the 1800s, as the Industrial Revolution takes off, atmospheric CO₂ concentrations begin an unprecedented upward climb, rising rapidly from 280 ppmv (parts per million by volume) in the early 1800s to a current level of 376 ppmv, 77 ppmv above the highest concentrations previously attained in the course of the preceding 400 thousand years.

Global Temperature

2. The rise in atmospheric CO₂ seems to correspond to–and likely be causing–rapidly rising global temperatures, as show in the graph at right from NASA. The graph shows temperature anomalies relative to the mean temperature of the years 1951 to 1980.

Debate about the temperature rise concerns how the temperature is measured. There is no one thermometer for the planet, so a single temperature is computed by taking measurements from various points around the globe or from satellites. Experts dispute the appropriate ways to do this; however, the general conclusion seems to be that the temperature is rising abnormally.

3. Suspicions are high that the phenomena has been a side effect of industrialization. According to the Washington Post,

An international panel of climate scientists said yesterday that there is an overwhelming probability that human activities are warming the planet at a dangerous rate, with consequences that could soon take decades or centuries to reverse.

Any argument against global warming would have to directly refute this data. We are faced with many pressing social issues, and they can become hopelessly complex unless we have some grounding in the data and use a combination of data and commonsense to weed out spurious arguments. In future posts, I’ll take a look at some of the counterarguments and see if any can overturn this.