Question

58. Are keeping global CO2 emissions constant at current level over the next several decades enough to eventually stabilize atmospheric CO2 concentration at 550 ppm and Explain why or why not? and how would global temperature and sea level respond to constant emissions?

Answer 1

Ans. The concentration of carbon dioxide (CO2), one of the most potent green house gases has been increasing since the industrial revolution. During the pre-industrial era the concentration of CO2 was about 280 ppm (parts per million or mg/L). However after the industrial revolution, during the 1800s the concentration of CO2 underwent significant change due to relentless use of fossil fuels. The concentration of CO2, increased to about 300 ppm by 1900 beginning, which rose to 340 ppm in the next 20 years. The current concentration of CO2, is about 414 ppm (February 2020). The National Oceanic and Atmospheric Administration (NOAA) in Mauna Loa observatory is the pioneer in the calculating the exact amount of concentration in the atmosphere since 1958. It has been given the name of Keeling curve after Charles David Keeling who first initiated this and shows the seasonal and annual change in concentration of CO2.

The current concentration of CO2 is too high and is the highest ever recorded in the history. So the concentration needs to be reduced. This is because this concentration has already brought about huge changes in the weather and climatic conditions. It is bringing about extreme weather changes; temperature increase has been breaking records every year. There is increase in frequency and intensity of deadly tropical cyclones. The result is inundation of coastal areas. There is spread of epidemics around the world and the worst case is that there are no medicines for the same. The current CO2 concentration cannot be continued to be in this state, it has to be reduced to the industrial levels. Only then we could lead to decrease in climate change and offset it. Letting the concentration of CO2 to increase to 550 ppm would wreck havoc.

If the emissions continue to increase like this, the earth will get warmer. There will be extreme heat waves during summer months and extreme cold waves during the winters. The temperature increase and fall will be record breaking. There will be thermal expansion of water and thus increase in sea levels. Thus the risk of inundation of the coastal areas will also be higher. Moreover the increase in temperature of water bodies will lead to increased formation of tropical cyclones, since they usually require 26.5oC to form and thus will intensify more due to the temperature increase of water. We know that water has a high specific heat capacity, thus it tends to retain more heat over land surface. So it will flood the coastal areas, destroy the beaches, and lead to water logging conditions in land areas, destroying the agricultural fields due to anoxic conditions and high salinity. If the concentration of CO2 is allowed to increase more, we will be reaching the tipping point from where the changes will be irreversible.