This, of course, means accidentally changing the weather, usually for the worse. Humanity has been very good at that, especially as a result of activities that lead to deforestation and pollution. It is now common knowledge that chemicals from cars and industry are destroying the ozone, and particulates from emissions also have an effect on precipitation. Cutting down forests in favor of croplands, urban construction, golf courses, and so on causes more sunlight to be reflected back into the atmosphere but can also cause urban heat islands. Animal agriculture can increase methane gas in the atmosphere, and irrigation of plants alters water distribution. All of these activities and more have noticeably changed natural weather patterns and the climate without humans intending to do so.