Global warming

The effects of global warming are the environmental and social changes caused (directly or indirectly) by human emissions of greenhouse gases. There is a scientific consensus that climate change is occurring, and that human activities are the primary driver.^[1] Many impacts of climate change have already been observed, including glacier retreat,^[2] changes in the timing of seasonal events^[2] (e.g., earlier flowering of plants),^[3] and changes in agricultural productivity.^[2]

Future effects of climate change will vary depending on climate change policies^[4] and social development.^[5]The two main policies to address climate change are reducing human greenhouse gas emissions (climate change mitigation) and adapting to the impacts of climate change.^[6] Geoengineering is another policy option.^[6]

Near-term climate change policies could significantly affect long-term climate change impacts.^[4][7] Stringent mitigation policies might be able to limit global warming (in 2100) to around 2 °C or below, relative to pre-industrial levels.^[8] Without mitigation, increased energy demand and extensive use of fossil fuels^[9] might lead to global warming of around 4 °C.^[10][11] Higher magnitudes of global warming would be more difficult to adapt to,^[12] and would increase the risk of negative impacts.

Source: Wikipedia