Dear Student,
The positive impacts of global warming include the increase is crop productivity due to fertilization effect which is caused due to increase level of carbon dioxide concentration in the atmosphere.
There are mainly harmful effects than any useful which are provided below.
Following are the effects of global warming:
(a) Changes in the direction of the flow of rivers: Global warming causes glacial ice to melt, leading to reductions in the snow cover. This in turn will reduce water availability and the hydropower potential of rivers.
(b) Rising sea levels: Due to rising temperatures, ice sheets melt, causing excess flooding. This may lead to islands getting submerged.
(c) Glaciers: Global warming may lead to a decline in the volume of water stored as ice; the melting of glacial ice raises the mean sea level. These mountain glaciers are significant sources of water for a balanced ecosystem.
(d) Agriculture: The agricultural production is likely to increase in some regions and decline in others because of climate change.
(e) Human health: Human health will be affected due to malnutrition, diseases and increased deaths.
(f) Depletion of the ozone layer in the stratosphere: CFCs escape into the stratosphere and cause the destruction of ozone.
Regards