You might be wondering, “So what if there’s a little climate change? What’s wrong with a couple of extra days at the beach?” Or maybe climate change is an issue just for polar bears and not humans.
Unfortunately, global warming doesn’t mean more fun in the sun – in many places, it could actually get way too hot for that – and it definitely isn’t just a polar bear problem. The climate crisis is real and it’s impacting people around the world today.
How do we know that changes in the sun aren’t to blame for current global warming trends?
But several lines of evidence show that current global warming cannot be explained by changes in energy from the sun:
- Since 1750, the average amount of energy coming from the sun either remained constant or increased slightly.
- If the warming were caused by a more active sun, then scientists would expect to see warmer temperatures in all layers of the atmosphere. Instead, they have observed a cooling in the upper atmosphere, and a warming at the surface and in the lower parts of the atmosphere. That’s because greenhouse gases are trapping heat in the lower atmosphere.
- Climate models that include solar irradiance changes can’t reproduce the observed temperature trend over the past century or more without including a rise in greenhouse gases.
Most climate scientists agree the main cause of the current global warming trend is a human expansion of the “greenhouse effect”— warming that results when the atmosphere traps heat radiating from Earth toward space.
Upwards of 800 skeptics (most of whom are not scientists) took part in the second annual International Conference on Climate Change—sponsored by the Heartland Institute, a conservative think tank—in March 2009. Keynote speaker and Massachusetts Institute of Technology meteorologist Richard Lindzen told the gathering that “there is no substantive basis for predictions of sizeable global warming due to observed increases in minor greenhouse gases such as carbon dioxide, methane, and chlorofluorocarbons.”
The consequences of changing the natural atmospheric greenhouse are difficult to predict, but certain effects seem likely.