Recently, somebody hacked into servers at the Climate Research Unit at East Anglia University, and they posted stolen emails on the internet. From these emails, climate change skeptics claim to have proof that anthropogenic (i.e. man-made) climate change is not occurring. With the climate summit in Copenhagen underway, some say that this “climategate” scandal could derail the process. Instead, I believe this situation allows us a moment to remember the facts regarding climate change.
To be clear, however, I am not writing to judge the contents of those emails sent between a small set of researchers using one method of analysis.
First, the Earth always has had a natural greenhouse effect that depends on CO2 and other “greenhouse gases”. Without this natural process, the Earth would be unable to trap solar radiation and warm the surface. Fortunately, so far, the Earth has had a stable carbon cycle that regulates the concentration of greenhouse gases in the atmosphere. In contrast to Earth, Venus has a runaway greenhouse effect due to its lack of carbon cycle, resulting in a mean planet temperature of 461 degrees Celsius.
Second, the CO2 concentration in the Earth’s atmosphere is increasing. Over the last 150 years, CO2 concentrations have risen from 280 to nearly 380 parts per million (ppm), and the concentrations are still increasing. While the exact concentration is an empirical matter, the trend is clear.
Third, humans have been burning fossil fuels in large quantities since the industrial revolution. Carbon dioxide is emitted by the burning of these fuels (coal, oil, wood, and natural gas).
Those three facts are not in dispute.
The only potential room for debate is the causal connections between human activities including those emissions, and the observed rise in CO2 concentrations. Since climate scientists cannot perform an experiment to test the causal link, the conclusion that humans are causing climate change can never be proven in the same way as results in other branches of science.
However, many scientists using many different methods conclude that enough evidence exists to prove beyond a reasonable doubt that humans are causing climate change. Moreover, this climate change is very dangerous and damaging. It is predicted to disrupt agriculture around the world, change ecosystems in ways that endanger biodiversity, increase extreme weather events like hurricanes and droughts, and raise sea levels enough to cover several island nations, much of Florida, other U.S. coastal cities, and about half of the nation of Bangladesh.
Therefore, it is our responsibility to devise a reasonable strategy to limit the effects of climate change. I don’t mean that the U.S. should or could do it all alone! Perhaps a small step by the U.S. might encourage other nations to get on board. The meeting in Copenhagen this month is another, hopefully productive, step in developing a global plan.
The situation in East Anglia should not distract from the facts. We need to keep our eye on the prize.