Climate Change 101
Climate change refers to any significant change in measures of climate (such as temperature, precipitation or wind) lasting for an extended period (decades or longer).
As through much of its history, the Earth’s climate is changing. Right now it is getting warmer. Most of the warming in recent decades is very likely the result of human activities. The National Oceanic and Atmospheric Administration’s (NOAA) State of the Climate Report and the National Aeronautics and Space Administration’s (NASA) Surface Temperature Analysis and the work of most independent climate scientists indicate that the average temperature of the Earth’s surface has increased by about 1.2 to 1.4ºF since 1900. But temperatures in the far north and far south have gone up by twice this amount in just the last 50 years, and science expects the rate of increase to grow more quickly over the next 50 years.
Other aspects of the climate are also changing such as precipitation patterns, storm movement and increased violent weather activity.
The Greenhouse Effect
Energy from the Sun drives the Earth’s weather and climate. The Earth absorbs energy from the Sun, and also radiates energy back into space. However, much of this energy going back to space is absorbed by “greenhouse” gases in the atmosphere. Because the atmosphere then radiates most of this energy back to the Earth’s surface, our planet is warmer than it would be if the atmosphere did not contain these gases. Without this natural “greenhouse effect,” temperatures would be about 60ºF lower than they are now, and life as we know it today would not be possible.
But during the past century humans have substantially added to the amount of greenhouse gases in the atmosphere by burning fossil fuels such as coal, natural gas, oil and gasoline to power our cars, factories, utilities and appliances. The added gases — primarily carbon dioxide (CO2) and methane — are enhancing the natural greenhouse effect, and likely contributing to an increase in global average temperature and related climate changes.
Source: EPA
For more information, visit the U.S. Environmental Protection Agency Kids Site and section on global warming.