What do we know about climate change? We know that Earth’s climate is changing—right here, right now.
How do we know? Scientific evidence. Not a single piece of evidence, but years of evidence. Greenhouse gases in
the atmosphere are rising. Temperatures are increasing. The growing seasons are changing. Ice sheets are melting.
Sea level is rising. Some extreme weather events, like heat waves and droughts, are becoming more frequent. Does
human activity (burning fossil fuels, agriculture, clearing land) affect climate change? The American Association for
the Advancement of Science (AAAS) reports that about 97 percent of climate scientists have concluded that
human-caused climate change is happening.
