Global warming is the long-term rise in the average temperature of the Earth’s climate system. It is a major aspect of climate change and has been demonstrated by direct temperature measurements and by measurements of various effects of warming. Global warming and climate change are often used interchangeably. It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century. The largest human influence has been the emission of greenhouse gases such as carbon dioxide, methane, and nitrous oxide. The effects of global warming include rising sea levels, regional changes in precipitation, more frequent extreme weather events such as heatwaves, and expansion of deserts. All acts that help avoid or reduce greenhouse gas emissions or acts that mitigate climate change are linked to this sub-category.