The challenges currently presented by our world are unprecedented in scale and urgency: climate change; deforestation; freshwater shortage; biodiversity loss; food insecurity; desertification and more, all of which require resolute address. The recent fires in Russia and tragic flooding in Pakistan have demonstrated the increasing severity of climate change at only 0.8° Celsius global average temperature rise, while also serving as stark precursors of what may be to come at 2°C or more.
One of the challenges with the current climate change mitigation approach is that it focuses too much on CO2 reductions, which have a very long lifetime. Dr. David Archer of University of Chicago in the US states: “The idea that anthropogenic CO2 release may affect the climate for hundreds of thousands of years has not reached general public awareness.” What this means is that any CO2 reduction today may lower future heating, but it will not bring about planetary cooling in our lifetimes. Instead, scientists and the Arctic Council are recommending focus we focus on reducing “shorter lived climate forcers,” to create rapid cooling by reducing methane, ozone and black carbon. Methane and black carbon are much more potent than CO2 in terms of trapping heat in the atmosphere, and methane dissipates out of the atmosphere in about 12 years. Black carbon goes in a few months and ozone in a few hours.
Averaged over 20 years, methane traps around 72 times more heat than CO2. Over a 5-year period, methane is seen to be even more potent, trapping around 100 times more heat than CO2. At the same time, methane leaves the atmosphere within a decade, while CO2 will stay around warming the planet for hundreds, possibly thousands of years.
The UN points out that livestock is the single greatest source of methane, at 36 percent of total anthropogenic methane. Furthermore, because methane is a building block of ozone, reductions of methane anywhere will reduce ozone, which is the third most prevalent greenhouse gas after CO2 and methane.
Short-lived Climate Forcers
Until recently, black carbon was not actually considered to have a warming potential at all.
Black carbon or soot is produced with the burning of vegetation and fossil fuels and is 680 times more heat trapping than CO2.
One of the biggest problems that black carbon creates is its absorption of heat from the suns rays, thus also warming the surrounding air. When this sooty residue lands on the snowy regions of our planet, not only does it melt the snows faster but it also darkens the surface, consequently causing less reflection of the suns rays back into the atmosphere.
Over 90 percent of the black carbon emitted by nations in the arctic region comes from agriculture, forest or peat fires. Scientists found that 60% of the black carbon particles in Antarctica were carried there by the wind from South American forests which are burned to clear land mainly for livestock grazing or the growing of soy for animal feed. Because over 80 percent of agriculture in the Amazon is for cattle grazing and raising soya for animals, reducing consumption of animal products is possibly the fastest way to reduce shorter lived climate forcers.
With black carbon staying in our atmosphere for a matter of a few weeks as opposed to CO2, which remains for 100 years or more, addressing black carbon is a key to mitigating climate change.
Two thirds of the plant and animal species on earth reside in tropical forests, of which 20 million hectares are destroyed every year releasing 2 billion tons of CO2 into the atmosphere, contributing 20-to 25% of global warming.
According to the UN Environmental Program Year Book 2009, and a World Bank report, our planet is quickly approaching “tipping points” which will cause drastic climate changes within the next few years. One of the greatest dangers is the collapse of the Greenland or West Antarctic ice sheets, entailing subsequent sea level rise of 20 feet which would submerge low-lying islands, coastal regions and flood river deltas upon which the global food supply depends, perhaps as early as 2100.
The UN reports that desertification is not only accelerating, also contributing to climate change, the loss of vegetation reducing carbon sinks and increasing emissions from biodegrading plants.