Is human activity a substantial cause of global climate change?
The US National Academies of Science, the National Aeronautics and Space Administration (NASA), and the National Oceanic and Atmospheric Administration (NOAA), and many others, say that greenhouse gas levels are rising due to human activities such as burning fossil fuels and deforestation which are causing significant climate changes including global warming, loss of sea ice, glacier retreat, more intense heat waves, stronger hurricanes, and more droughts. They contend that climate change requires immediate international action to prevent dire consequences.
