We are pumping an estimated 90 million tons of carbon dioxide per day into the atmosphere through our use of fossil fuels – oil, coal and natural gas. Carbon dioxide is a greenhouse gas which absorbs heat. As the amount of atmospheric carbon dioxide increases so must the global temperature (see my posting entitled “Solar Activity, Greenhouse Gas Levels and Climate Change Our Earth.”)
The planet removes carbon dioxide from the atmosphere by rock weathering - when the planet is moving towards a glacial period - which causes a decline in the global temperature (see my posting entitled “Carbon Cycle”). During the peak of glacial periods the atmospheric carbon dioxide levels are about 170 ppm and at the peak of interglacial periods about 300 ppm. Today the carbon dioxide level is 395 ppm! It takes about 100,000 years for the carbon dioxide to fluctuate between 170 and 300 ppm during the natural glacial/interglacial cycles. However, through our use of fossil fuels the current rise in the level of atmospheric carbon is occurring in decades!
Rock weathering is an extremely slow process because atmospheric carbon dioxide reacts with water and rocks to form calcium bicarbonate. Calcium bicarbonate enters the river water and eventually ends up in the ocean where it becomes part of the shell of various marine organisms such as zooplankton and shell fish. When these animals die the shells containing the bicarbonate fall to the ocean floor and over time are buried in sediments and eventually are converted to fossil fuel and rock. This process takes millions of years. Fossil fuels are carbon sinks which keeps the carbon out of circulation for millions of years.
Our current dilemma is that the carbon dioxide generated from the burning of fossil fuels can’t be transferred by rock weathering from the atmosphere into the fossil fuel/rock carbon sink fast enough. Thus most of this excess carbon dioxide remains in the atmosphere and the global temperature goes up which triggers the extreme weather we have been experiencing in recent years. A recent NASA study stated that extreme weather should statistically occur only on 0.3% of the planet at any given time. The most extreme weather year in the past was 1941 in which 2.7% of the planet had extreme weather at any given time. However, from 2006 to 2011 about 10% of the globe had extreme weather at any given time. The results are not yet in for this year but it will be worst!
The carbon dioxide concentration in the atmosphere and the ocean –another carbon sink – are in equilibrium. This means as the atmospheric level of carbon dioxide goes up so must its level in the ocean. This leads to ocean acidification (see my posting entitled “Atmospheric Carbon Dioxide Levels and Ocean Acidification”). Prior to the industrial revolution the pH of the ocean was around 8.2 but today it is 8.05. This doesn’t seem like a significant drop but it is because pH is on a logarithmic scale. This lower pH is already causing shell fish and sea turtles to have softer shells and along with higher temperatures is causing the destruction of coral reefs.
The choice is ours! We either continue “business as usual” with our use of fossil fuels or we convert to carbon neutral energy sources. If we continue “business as usual” we will eventually reach a climate tipping point which will have catastrophic consequences (see my posting entitled “Climate Crisis: Is the Climate Reaching Tipping Points”). The time to start converting to renewable energy sources in now – not when we reach a tipping point because by then it will be too late!