Causes of Climate Change

Biochemistry and changes in climate

Climate change is being affected by many human activities in a variety of ways, both direct and indirect; however, what is considered the largest anthropogenic factor contributing to climate change are CO2 emissions from human activities [3,10,11]. This is primarily due to fossil fuel combustion which is responsible for more than 75% of the human caused CO2 emissions while the rest is related to land use changes such as deforestation. The concentration of CO2 is now at 379 ppm which is most likely higher than anything seen in the last 650 kyr with the increase in CO2 never previously exceeding 30 ppm in 1kyr while this has now risen to 30 ppm in just 17 years [10]. This atmospheric increase in CO2 use is known to be caused by humans due to the ratio of heavy to light carbon atoms that are a signature of fossil fuel carbon [10].

CO2 is one of the major greenhouse gases responsible for global warming [3,10]. The increase in temperature is caused by the greenhouse gases interacting with infrared radiation that would normally escape the atmosphere, and instead reflecting the radiation back to the surface [11].

This picture shows the natural carbon cycle as well as anthropogenic causes of increased carbon[10]

Above is a diagram of the carbon cycle, which is an essential part in maintaining the balance between many of the natural processes that occur on the Earth. Carbon sinks are major component of these, taking up much of the C02 produced. These carbon sinks have been unable to handle the massive amounts of anthropogenic C02 that are now produced annually however. This amount is now 6.1 billion tons and while the carbon sinks are able to take up some of this amount, they unable to take it all, leading to a net gain of 3.2 billion tons to the atmosphere annually[11]. This increasingly large amount of CO2 adding to the atmosphere each year shows the continual increase of greenhouse gases that only serve to further global climate change.