What is climate change?
The temperature of the world is rising. Fluctuations in temperature over time are normal, but the current changes are unprecedented and threatening. Naturally occurring gases (such as carbon dioxide, nitrous oxide and methane) in the atmosphere form a ‘blanket’ round the earth, trapping the heat from the sun. Since the Industrial Revolution, our burning of fossil fuels has increased levels of these greenhouses gases in the atmosphere, trapping more heat. Climate change can bring both unstable, extreme weather patterns and long-term trends of changing rainfall and temperatures to which all life will need to adapt. The Intergovernmental Panel on Climate Change predicts greater climate changes are yet to come.
Climate includes patterns of temperature, precipitation, humidity, wind and seasons. “Climate change” affects more than just a change in the weather, it refers to seasonal changes over a long period of time. These climate patterns play a fundamental role in shaping natural ecosystems, and the human economies and cultures that depend on them. Because so many systems are tied to climate, a change in climate can affect many related aspects of where and how people, plants and animals live, such as food production, availability and use of water, and health risks. For example, a change in the usual timing of rains or temperatures can affect when plants bloom and set fruit, when insects hatch or when streams are their fullest. This can affect historically synchronized pollination of crops, food for migrating birds, spawning of fish, water supplies for drinking and irrigation, forest health, and more. Some short-term climate variation is normal, but longer-term trends now indicate a changing c
Although dynamical systems, like Earth’s climate system, are full of complicated processes that lead to chaotic variations, changes to external forcing of the system can lead to significant changes. For the Earth’s climate, we usually think of trends in global average quantities (especially surface temperature) as indicative of climate change. When the trend leads to a change larger than the natural variability, a statistically significant change most certainly has occurred.
Climate change refers to the variation in the Earth’s global climate or regional climates over time scales ranging from decades to millions of years. Changes may be driven by internal processes, external forces or, most recently, by human activities. Recent climate changes have been attributed to global warming, which is caused by the increase in atmospheric concentration of greenhouse gases, trapping heat near the Earth’s surface.
