The earth’s atmosphere is heating up because of an accumulation of greenhouse gases in the atmosphere. These gases (mainly carbon dioxide, CO2 and methane, CH4, if you want to pull out your periodic table from high school chemistry) are released when we burn fossil fuels like oil, coal and natural gas for transportation, heating and cooling, manufacturing and so on.

Another major producer of greenhouse gases is the burning of rain forests in Latin America, Indonesia and elsewhere. Cows also produce methane when they eat and digest their food, but it might be wise to leave the details of that aside. We’ll confine ourselves to the human causes here.

So what do greenhouse gases actually do? They trap heat closer to the Earth, the same way having a thick blanket on your bed at night traps your body heat close to your body. Since the Industrial Revolution began, humanity has been piling on the blankets.

We’ve built our civilization on the power generated by fossil fuels like coal and oil. Those fuels have given us a dramatically better standard of living, but they also add to the greenhouse gases in the atmosphere.

For the past 150 years, the average temperature of the Earth’s atmosphere and oceans has been rising, and lately this seems to be speeding up. For example, the eleven hottest years on record have all occurred since 1995.

Carbon dioxide levels are now approximately 40 percent higher than they were at the start of the Industrial Revolution, and they have reached levels not seen in the atmosphere in 20 million years. Scientists say that unless we curb global warming emissions, average U.S. temperatures could be 3.2 to 7.2 degrees higher by the end of the century.

What Could Happen?

A 3.2 to 7.2 degree rise in temperature may not sound like much, at least to those who aren’t scientists. But this could have devastating consequences.

Here’s what worries scientists:

• Coastal Flooding. A growing concern is that the large ice sheets of Greenland and West Antarctica will likely melt more quickly in the future, accelerating the rise in sea levels and threatening many coastal communities. The Dutch, much of whose land is already below sea level, are so concerned they have begun experimenting with floating houses.
• Extreme Weather. Many scientists believe that the increase in heat waves, episodes of extreme rainfall and the intensity of hurricanes may be related to global warming – and that we can expect harsher weather if the warming trend is allowed to continue.
• Droughts. Rising temperatures may increase the number of droughts, which will in turn affect food crops across the globe. Many scientists are warning that we may already be seeing agricultural problems as a result of global warming.
• Economic and Social Instability. Problems like coastal flooding, extreme weather and crop failures all impact the economy and social stability. People who live in coastal areas may be displaced or have to deal with repeated flooding. Extreme weather like hurricanes and tornadoes destroys homes and businesses, sometimes entire communities. Droughts and crop failures lead to food shortages and rising prices.

Problems like these are devastating anywhere. Keep in mind that when it comes to coping with these catastrophic events, the United States is better off than many countries. We’ve got money and technical savvy to adapt. The consequences in other poorer parts of the world, like Africa, could be much worse.

Naturally with consequences like these, the better part of valor is to do whatever can be done to slow the process of climate change and try to hold it to levels to which we can adapt. The overwhelming majority of scientists warn that we cannot afford to wait and see what happens. We can’t take that doubt about specifics as a reason to sit on our hands and hope that the problem resolves itself.

Since it’s called global warming, the United States obviously isn’t the only player here. So far, the U.S. has been reluctant to join international agreements on climate change such as the Kyoto Protocol which sets binding targets for reducing greenhouse gas emissions.

President Bush proposed a plan for voluntary reductions instead and the Senate objected to the fact that the Kyoto treaty does not set targets for emerging economies like China and India. One hundred and eighty one countries have signed and ratified the treaty, and although the U.S. has not, many states and cities in the U.S. have passed resolutions endorsing its terms.

So How Is The U.S. Doing Compared To Other Countries?

Many European nations like Britain and France, and Japan as well, have acted much more aggressively on cutting emissions. They rely more on nuclear power and natural gas than we do and rely much more on mass transit and rail.

The story is mixed in developing countries, especially the economic powerhouses like China and India. Because their economies are growing so rapidly, they use much more energy and produce more greenhouse gases than they have in the past. At the same time, they have the chance to start fresh with cleaner and more efficient technologies if they can be persuaded to do so.

With China and India producing more greenhouse gases these days, some believe these countries deserve more of the blame for global warming. But it’s not really so clear who is guiltiest. Global warming stems from accumulated gases in the atmosphere, so industrialized countries like the U.S. and those in Europe have played a major role in creating the problem since oil and coal have been the centerpieces of their economies for decades now.