Climate is the long-term, prevailing pattern of temperature, precipitation, and other weather variables at a given location, described by statistics, such as means and extremes. The climate includes conditions in the atmosphere and ocean, and is often described in terms of the intensity, frequency, and duration of severe and non-severe weather events. Over Earth's history, indications of climate change have been recorded in fossils and ice core samples. Climate change can result in extended periods of heat and drought at one extreme and extensive glaciation at the other. Current patterns in climate data show that our planet's global surface temperature is rising. This change is linked to the dramatic increase in greenhouse gases in the atmosphere that has occurred over the past two centuries. Understanding climatic processes and the resulting impacts of a changing climate are important as every living organism on Earth is affected.
Carbon is the chemical backbone of life on Earth and a key element in many important processes. Carbon compounds help to regulate the Earth’s temperature, make up the food that sustains us, and provide a major source of the energy to fuel our global economy.
You may adapt your wardrobe and activities to the seasons, grabbing a heavy coat and skis in winter or instead, a swimsuit and snorkel in summer. Although ecosystems, plants, and animals cannot adjust their wardrobe quite so easily, they do make changes that help them survive seasonal conditions caused by the annual dance of the sun and Earth.
Impacts from climate change are happening now. Ecosystems and human communities are currently being affected. These impacts extend well beyond just an increase in temperature. They are happening in the United States, and across the globe. Multiple sectors of our our society, spanning across regional boundaries, are being affected. Already impacted are things that we depend upon and value: water, energy, transportation, wildlife, agriculture, ecosystems, and human health.
What is Climate? Some say that climate is what you expect and weather is what you get. More formally, climate is the long-term average of temperature, precipitation, and other weather variables at a given location. Every 30 years new averages are calculated by climate scientists. The normal high and low temperatures reported on your local weather forecast come from these 30-year averages. Although climate describes conditions in the atmosphere (hot/cold, wet/dry), the chemistry of the atmosphere, and influences of the ocean, land, and sun all affect these conditions. If we want to understand and predict changes to local or global climate, all of these factors must be monitored.
