explain how human activities lead to global warming?
Answers
Answer:
The effects of global warming are the environmental and social changes caused (directly or indirectly) by human emissions of greenhouse gases. There is a broad scientific consensus that climate change is occurring, and that human activities are the primary driver.[1] Many physical impacts of climate change have already been observed, including extreme weather events, glacier retreat,[2] changes in the timing of seasonal events[2] (e.g., earlier flowering of plants),[3] changes in agricultural productivity,[2] sea level rise, and declines in Arctic sea ice extent.[4] The physical effects of human-caused climate change depends on the extent of prevention efforts (i.e., reducing greenhouse gas emissions). Ocean acidification is not a consequence of global warming, but instead has the same cause: increasing atmospheric carbon dioxide.
The social impact of climate changes will be further affected by our efforts to prepare for and adapt to changes that do occur.[5][6] Climate engineering is another policy option, although there are uncertainties regarding its effectiveness and little is known about potential side effects.[7] Climate change is likely to put pressure on some food crops and on fresh water supply. This in combination with extreme weather events, likely leads to negative effects on human health. Climate change can be a driver of human migration.
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]
Answer:
The largest known contribution comes from the burning of fossil fuels, which releases carbon dioxide gas to the atmosphere.
Greenhouse gases and aerosols affect climate by altering incoming solar radiation and out-going infrared (thermal) radiation that are part of Earth’s energy balance. Changing the atmospheric abundance or properties of these gases and particles can lead to a warming or cooling of the climate system.