In one of this week's installments of the comic strip Mallard Fillmore, the strip claims thatglobal warming is being caused by the sun, and it cites two sources -- National Geographic news, and the Danish National Space Center. But reader beware. I haven't found a reference in National Geographic or on their website that claims the sun is causing global warming (I did find one article that claims the opposite), but that doesn't mean that a news story to that effect isn't buried somewhere. Meanwhile, the Danish Science Center does report that the sun is responsible for some global warming, but on the same page, they go on to say "That there exists a significant contribution from solar activity variations to global temperature increase does not, however, exclude other contributions to the rising global temperature, natural as well as human."
So, does the sun contribute to global warming? Yes, to some extent -- the latest numbers I hear are that the sun may cause, at most, 25% of observed global warming. But that leaves 75% to be accounted for, and the answer is unambiguously that people are responsible for most, if not all, of that. In February, scientists released a report that states that global warming is occurring and that humans are responsible. Among climate scientists, there is no significant debate about these facts. Yes, you will always be able to find some scientists who disagree. But the vast majority of scientists agree that humans are the primary cause of global warming. In fact, if anything, the February report likely understates the evidence for human impact on the climate. This is because the scientists had to get unanimous approval of politicians before issuing the report, including politicians from governments that ignore or downplay global warming, such as the U.S. and China.
Today, a second in a series of reports on global warming was released. This report details how scientists believe global warming will impact the environment, including impacts on humans. Yes, much in this report is speculation, but it is informed speculation based on nearly 29,000 separate data sets, climate models, research reports, etc. This isn't idle speculation -- it is a prediction. And again, political pressures forced the report to be watered down from what scientists truly believe.
The facts are that global warming is occurring, people are the primary cause, and the effects of ignoring global warming are dire for people as well as the environment. But let us be positive -- we can stop it, and without massive, sudden changes in our lifestyles. In fact, the sooner we start to change, the less drastic any human action has to be! The more we put off changes, the more drastic we will have to change in the future.
History shows that humans can change and make positive impacts on the environment. When I was in high school, the ozone hole was a big scare. Chemicals used by humans were causing a hole to develop in the ozone layer, and that hole was growing from year to year. We banded together as a species and stopped most production of those chemicals, and now the ozone hole is stabilized, and in some years appears to be shrinking. In the 60s and 70s, smog was a major problem in most major U.S. cities, but emissions controls on cars and industry has greatly reduced (though not eliminated) the problem. We have also eliminated or reduced many of the most pressing threats to our water supply through the Clean Water Act. And when certain pesticides were threatening many birds and other animals with extinction, we eliminated most of that threat. In none of these cases did we have to give up our way of life -- we made changes, sure, but the economy was not plunged into an endless depression, most of us in the U.S. still have our own cars, and our food supply has not been decimated by insects.
The same can be true for global warming. There are changes that we can and must make that will cost money and will be inconvenient, but, in the grand scheme of things, these changes are minor. First and foremost, we must reduce our use of fossil fuels and change to become completely dependent on renewable resources. This can be a gradual change, occurring over decades, but we must start that change. Energy efficiency can start with very simple changes. Replace normal incandescent light bulbs with compact fluorescents. During the summer, let the temperature in your house be one or two degrees warmer. If you have a use for a truck or SUV, that's fine. But also own a smaller car that you use when you don't need the carrying capacity of a larger vehicle. Shut down your computer when you are not using it.
These steps are small and won't solve the problem, but they are a beginning. We can be reasonable about our response to global warming -- we don't have to regress back to Stone Age technology. But we do have to get started. And the sooner we get started, the less dramatic the impact on our lives will be. Let's give the poor sun a break, admit that we are causing major and negative changes in the Earth's climate, and start working on solutions.
Added on April 9: The web site for the UN taskforce on global warming, the Intergovernmental Panel on Climate Change, is here.