Graph shows concentrations of atmospheric Co2 for the last 800,000 years, with measurements, starting from 1958, made at Mauna Loa in Hawaii. - Image courtesy of World Meteorological Organization
Scientists monitoring atmospheric concentrations of CO2 from a mountaintop in Hawaii recently reported that the presence of this greenhouse gas exceeded 400 parts per million (ppm) for the first time in at least three million years – a period when temperatures were much warmer than today. The significance of this seemingly dry statistical trend is stunning as reported in the New York Times:
From studying air bubbles trapped in Antarctic ice, scientists know that going back 800,000 years, the carbon dioxide level oscillated in a tight band, from about 180 parts per million in the depths of ice ages to about 280 during the warm periods between. The evidence shows that global temperatures and CO2 levels are tightly linked.
In addition to the location in Hawaii, several other Global Atmosphere Watch stations from the Arctic to the Equator reported CO2 concentrations exceeding 400ppm.
Experts believe that in order to limit warming to 2°C – a goal based on expected impacts – concentrations should rise to no more than 450 ppm, a level we may reach in only about 25 years based on current trends.
We’ve all had our moments of frustration with the unending negotiations on mechanisms to control carbon dioxide emissions. In the last Conference of Parties held at Durban in 2011, it was decided that the global deal for the post Kyoto framework will only be reached by 2015.
Meanwhile, the climate clock is ticking: countries continue to face the impacts of climate change with the poorest being hardest hit. Science has shed the spotlight on a “parallel track” which could help us deal with part of the climate change problem in a faster, cheaper way – it is tackling short-lived climate pollutants (SLCPs), primarily black carbon, methane, and hydrofluorocarbons (HFCs).
These pollutants, while being extremely potent in terms of their global warming potential are short-lived in the atmosphere. For example, black carbon persists in the atmosphere for about two weeks (compared to CO2 that lives for up to 100 years) and is 917 times more warming than CO2 over a 100 year timeframe (and 3,320 times over 20 years).So, action on SCLPs can help buy time in addressing the more important and longer-term greenhouse gas (GHG) emissions.