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]
Anthropogenic forcing has likely contributed to some of the observed changes, including sea level rise, changes in climate extremes, declines in Arctic sea ice extent and glacier retreat.
[4] Future effects of climate change will vary depending on climate change policies[5] and social development.[6] 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.[7] Geoengineering is another policy option.[7] Near-term climate change policies could significantly affect long-term climate change impacts.[5]
[8] Stringent mitigation policies might be able to limit global warming (in 2100) to around 2 °C or below, relative to pre-industrial levels.[9] Without mitigation, increased energy demand and extensive use of fossil fuels[10] might lead to global warming of around 4 °C.[11][12]
Higher magnitudes of global warming would be more difficult to adapt to,[13] and would increase the risk of negative impacts.[14] This article doesn't cover ocean acidification, which is directly caused by atmospheric carbon dioxide, not global warming.
problems in environment
Global warming
Ozone depletion
Climate change
Acid rain
