Climate change gets a lot of attention in the media. While everyone agrees the climate is changing, some suggest recent changes are a result of natural weather cycles. Despite this, the majority of scientific experts believe these changes aren’t occurring at a natural rate and the actions of humans are speeding up and amplifying the effects of global warming, resulting in climate change. So, what's the deal?
Fluctuations in the Earth’s climate are normal and have happened throughout history (take the ice ages, for example). However, those changes took place over the span of thousands to millions of years. Currently, climate change is taking place within decades, which is much faster than the historical trend.
- Fast Fact: The hottest decade ever recorded by NASA since 1880 was between January 2000 and December 2009.
What's the difference between global warming and climate change?
The term "global warming" refers to the observation that the Earth is getting hotter with each passing year. Climate change, on the other hand, refers to the long-term changes in weather patterns around the world. Many people assume global warming means milder winters and hotter summers. While this may be true in some cases, it isn’t true for everyone because the Earth’s weather patterns are complex. An overall increase in atmospheric temperature can affect wind and ocean currents that are able to move heat around the world, causing some places to be warmer and others to be colder.
- Fast Fact: Global temperatures have been rising at a steady rate since the 1980s.
What is causing global warming?
Most scientists believe that one of the major factors contributing to global warming is the increase in carbon dioxide (CO2) levels in the atmosphere by the burning of fossil fuels. CO2 is a greenhouse gas (GHG). GHGs function by trapping heat from the sun, similar to how a greenhouse traps heat from the sun to help plants grow. GHGs are present within the normal atmosphere, but are a problem when concentrations are too high.
- Fast Fact: CO2 levels from historic times can be measured in the tiny air bubbles that were trapped at the time the ice was frozen. Based on this, scientists have shown that CO2 levels are the highest they have been in the last 650,000 years.
Atmospheric CO2 levels have been increasing since the Industrial Revolution in the 1700s, when machines were invented to do everything from manufacturing to transportation. More sophisticated machines used fossil fuels as an energy source. Our primary source of energy still comes from the burning of fossil fuels, such as natural gas and gasoline for vehicles. New technologies are being used to reduce dependence on fossil fuels, a non-renewable resource, which could help reduce CO2 emissions.
Article first published February 25, 2011.
Photo Credit:1917 photo captured by Louis H. Pedersen; 2005 photo taken by Bruce F. Molnia. Credit: The Glacier Photograph Collection, National Snow and Ice Data Center/World Data Center for Glaciology.