- Carbon dioxide levels in the atmosphere have fluctuated throughout time. 100 million years ago, levels were many times higher than what they are now. 500mya atmospheric carbon levels were around 20 times higher than today. Currently, carbon levels are on the rise, and this is having many impacts.
- Lots of intense research has gone in to trying to find the impacts on the land, but so far, results have been quite unclear because it has only been a short period of time. Some of the estimated impacts are as follows:
- Increased uptake of CO2 by plants since 1960 with around 25% of emissions removed from the atmosphere by plants.
- Increased temperatures warm up the land in some Tundra areas, warming of land increases rate of decay of accumulated dead organic matter leading to release of gases like carbon dioxide and methane.
- Increased temperatures mean an elongated growing season with more plant growth and higher rates of evapotranspiration needs more water, but this limits growth, as there is not necessarily enough water available
- With more CO2 available in the atmosphere, there is more photosynthesis and more plant growth, this process is ‘carbon fertilisation’.
- Some impacts have been added to or caused by human land use decisions:
- More intensive agriculture with more crops from less land increases take up of carbon dioxide.
- More wildfires are being extinguished, woody material builds up which is storing carbon.
- Farmland in mid-latitudes were abandoned in early 20th century, replaced by trees which store more carbon than crops.
