With the release of its report “Climate Change 2007” by the Intergovernmental Panel on Climate Change, the issue of global warming has surfaced in the press, and in the government, yet again. The report basically says that scientists agree that the Earth’s temperature increase is being caused by greenhouse gas emissions, and that there is evidence in the reduction of glaciers, increase in sea water temperature, and a number of biological indicators such as the migration patterns of birds. The implications for the future will result in further reduction of glacial ice, sea level rise, sea level temperature rise, and many other effects. Still, there are many who claim the whole idea of global warming is a hoax. Is it?

The short answer is no. We are slow to accept new ideas. I am reminded of how we have been very slow to accept the findings of science when they fly in the face of our political or religious views. There are many examples in science. Here are some historical examples showing how slow we are to accept new ideas.

Copernicus. The view of the world introduced by Copernicus (he was so afraid of the reaction that his book was not published until he was on his deathbed). It took hundreds of years for the Catholic Church to finally move from an Earth centered universe to a Sun-centered, and even that proved to be wrong with the discovery of galaxies.

Galaxies. The sun is not the center of the universe, but merely one star in one galaxy among billions. The existence of galaxies greatly expanded our concept of the universe and raised questions about our place in the universe.

Age of the Earth. Then geologists threw another curve ball when evidence was amassed that the Earth is not very young, but in fact, 4.5 billion years old, and the universe (since the Big Bang) is 15 billion years old.

Beginnings. And, finally, I would add that science has clearly shown that the Universe began as a small-grapefruit size, and exploded with a Big Bang, 15 billion years ago. And instead of living in a fixed, stationary Universe, the stars and galaxies are expanding away from the original Big Bang. We live in an expanding universe, not a static one.

So, I am not surprised that many people, including the U.S. government has turned away from scientific findings supporting the fact that the Earth is heating up, and the cause is human induced by greenhouse gas emissions.

An important question concerning global warming is this: Is the Earth’s surface average temperature changing?

According to research funded by the U.S. government (isn’t it strange that the same government doesn’t use the results of its own funded scientific research), and posted on the EPA Climate Change website, “records from land stations and ships indicate that the global mean surface temperature warmed by between 0.7 and 1.5ºF during the 20th century (see Figure below).

The EPA reports that “these records indicate a near level trend in temperatures from 1880 to about 1910, a rise to 1945, a slight decline to about 1975, and a rise to present (NRC, 2006). Warming is now occurring over most of the globe and is consistent with the global retreat of mountain glaciers, reduction in snow-cover extent, the earlier spring melting of ice on rivers and lakes, and increases in sea-surface temperatures and ocean heat content.”

The graphic below shows sea ice change since 1979 in the Arctic. According to NASA, Arctic sea ice has been decreasing at a rate of 9% per year, with the most significant change in the last three years. This continuation will have at least two effects; increase in sea level; contribution to increasing global temperatures as glacial ice reflects solar energy; less glacial ice means more absorption of solar energy and higher air temperatures.

Finally we can summarize and say that “research to detect climate change and attribute its causes using patterns of observed temperature change shows clear evidence of human influences on the climate system due to changes in greenhouse gases, aerosols and stratospheric ozone (EPA).

Future climate change

From the EPA website, scientists agree that “greenhouse gas concentrations in the atmosphere will increase during the next century unless greenhouse gas emissions decrease substantially from present levels. Increased greenhouse gas concentrations are likely to raise the Earth’s average temperature, influence precipitation and some storm patterns as well as raise sea levels. The magnitude of these changes, however, is uncertain.”

Often, the hoax advocates will pick up on the word “uncertain” and use it to deride the scientific research, and make the claim that this uncertainty indicates “bad science” and the therefore the results should not be trusted. Uncertainty in science does not mean “bad science,” instead it speaks more to the range of the data, and the extent to which interpretations can be made.

I once heard a science teacher (Bob Maxwell) when giving a talk to American and Russian high school students who were involved in collaborative environmental research tell the story of the cooked chicken. It went this way. I can’t tell it as well as Bob did. Here goes. He had two pots nearly full of water (one cold, and one boiling) each on a separate portable heating source. He asked the students to imagine what might happen if he put a chicken in the pot of cold water, and then heated the water ever so slowly; he also asked what might happen if he put the chicken in the boiling water. In the end you would get the same effect, a “cooked chicken.” But getting there would be entirely different. The increased temperatures that we observe on the Earth is similar to the cold water being heated slowly; the chicken get cooked, but doesn’t even know its happening.

We aren’t cooked, but don’t you think we ought to pay attention to what the Earth is showing us regarding temperature change?

Teaching resources on global warming and climate change:

Three (scientific) views on Global Warming
EPA Global Warming/Climate Change Site
Global Warming from Wikipedia
Global Warming from the Union of Concerned Scientists (includes teaching and curriculum ideas)
Findings of the IPCC Fourth Assessment Report: Climate Change Science
An Inconvenient Truth
Global Warming Frequently Asked Questions from the National Climatic Data Center, U.S. Department of Commerce
Research Articles from Google Scholar Search
Papers by James Hansen and Others on Global Warming (Hansen is one of the leading government researchers on global climate change.)