7 Module title: : Introduction to Climate Education “GLOBAL WARMING” VS. “CLIMATE CHANGE” Global warming is just one aspect of climate change. It’s a term used to describe the recent rise in the global average temperature near Earth’s surface, which is caused mostly by increasing concentrations of greenhouse gases (such as carbon dioxide and methane) in the atmosphere. The terms “global warming” and “climate change” are sometimes used interchangeably, but warming is only one of the ways in which climate is affected by rising concentrations of greenhouse gases. THE GREENHOUSE EFFECT Greenhouse gases, such as CO2, methane, and nitrous oxide, act like a blanket around the planet. They trap energy in the atmosphere and cause it to warm. This phenomenon, called the greenhouse effect, is natural and necessary to support life on Earth: without it the Earth’s average temperature would be around -18°C. But scientists agree that the continuing build up of greenhouse gases in the atmosphere— caused mainly by the burning of fossil fuels for energy—will upset the natural energy balance and change Earth’s climate, with potentially dangerous risks to human health, infrastructure, the economy, and ecosystems What is the evidence that shows the climate is changing? Scientists have documented long-term changes around the world in temperature, precipitation, sea level, and the amount of heat stored in the ocean. Especially dramatic changes are underway in the Arctic, whervve warming is amplified by powerful feedbacks. Reductions in sea ice, land-based ice, and snow cover, along with the thawing of permafrost, are having profound impacts in the Arctic and beyond. Rising sea levels, caused mainly by the expansion of seawater as it warms, along with billions of tons of water added to the ocean each year from melting glaciers, ice caps, and ice sheets, are affecting coastal communities in many parts of the world. Changes in the length of growing and pollen seasons, the timing of bird migrations, and range shifts in plants and wildlife provide still more evidence for recent changes in climate. How do we know humans are causing climate change? Climate scientists have concluded that humans are largely responsible for the climate change that has occurred since the 1950s. Human activities— such as burning fossil fuels for energy, cultivating crops, raising livestock, and clearing forests—are releasing greenhouse gases into the atmosphere. These greenhouse gases are being emitted faster than forests and the oceans can remove them, causing them to build up in the atmosphere. The atmospheric concentration of CO2 has increased by more than 40% since pre-industrial times, and the current CO2 level is higher than it has been in at least 800,000 years.
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