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9 Sep, 2014 19:43

Level of greenhouse gases in atmosphere reaches record high in 2013 – UN agency

Level of greenhouse gases in atmosphere reaches record high in 2013 – UN agency

Greenhouse gas levels in the atmosphere reached a record high in 2013, largely due to a massive increase in carbon dioxide emissions. There has also been a surge in levels of other greenhouse gases, as well as enhanced ocean acidification.

That’s according to the annual Greenhouse Gas Bulletin compiled by the World Meteorological Organization’s (WMO) Global Atmosphere Watch (GAW) network. The WMO is a specialized agency of the United Nations.

The Greenhouse Gas Bulletin reports on the atmospheric concentrations of greenhouse gases and not their emissions. Emissions are what gets pumped into the atmosphere, whereas concentrations are what is left in it after the complex system of interactions between the oceans, biosphere and atmosphere. While half of the emissions are soaked up by the oceans and the biosphere, the rest is stored in the atmosphere, where it remains for a very long period.

This Year’s Greenhouse Gas Bulletin found the concentration of carbon dioxide (CO2) in the atmosphere was 142 percent of pre-1750 levels (the beginning of the industrial era), while methane and nitrous oxide (N2O) were 253 percent and 121 percent, respectively.

The analysis showed that between 2012 and 2013 CO2 levels increased more than in any other year since 1984. Globally the amount of CO2 in the atmosphere hit 360 parts per million in 2013, an increase of 2.9 parts per million since 2012. The symbolic milestone of 400 parts per million will likely be reached in either 2015 or 2016.

Preliminary data indicated that this was related to a reduced intake of CO2 into the biosphere as much as to steadily increasing emissions.

CO2 accounted for 80 percent of the 34 percent increase in radiative forcing by long lived greenhouse gases from 1990 to 2013. Radiative forcing is a term used in climate science, which means the amount of sunlight which is reflected back into space and therefore not absorbed into the atmosphere. An increase in radiative forcing means that more heat is absorbed into the atmosphere, as a direct result of more greenhouse gases.

The second long lived greenhouse gas after CO2 is methane. While around 40 percent of methane emissions are released into the atmosphere from natural sources such as wetlands and termites, the rest comes from human activity, like landfills and biomass, fossil fuel extraction and cattle breeding. Since 2007, atmospheric methane has been rising again after flattening out for a while and in 2013 hit a record high of 1,824 parts per billion.

Nitrous Oxide (N2O) is also a big problem for the atmosphere, as although there is much less of it than CO2, its impact on the climate over 100 years is 298 times greater. N2O also plays a role in the destruction of the stratospheric ozone layer, which protects life on Earth and particularly vulnerable pale-skinned people from the ultraviolet rays of the sun. Although about 60 percent of N2O is emitted from natural sources, the remainder comes from human activity such as fertilizer use and industrial processes.

The Secretary General of the WMO, Michel Jarraud, said that the Greenhouse Gas Bulletin makes grim reading and action is needed before it’s too late.

“We know without any doubt that our climate is changing and our weather is becoming more extreme due to human activities such as the burning of fossil fuels. The concentration of carbon dioxide in the atmosphere actually increased last year at the fastest rate for nearly thirty years. We are running out of time,” he said.

Reuters / Bobby Yip

Ocean acidification

For the first time the Greenhouse Gas Bulletin included a study on the acidification of the oceans; the WMO collaborated with the International Ocean Carbon Coordination Project (IOCCP)as well as a number of other ocean research intuitions including the international Oceanographic Commission of UNESCO (IOC-UNESCO).

The oceans absorb about a quarter of all human produced CO2. While this does reduce the amount of CO2 released into the atmosphere it has a very bad effect on the oceans, which is complex and not yet fully understood.

Increased ocean CO2 intake alters the marine carbonate system, which directly leads to higher acidity.

The current rate of ocean acidification is unprecedented in the last 300 million years. Using data from Paleo archives (a process, which examines coral, ice cores and fossils) and projections form Earth system computer models; ocean acidification is projected to accelerate at least until the middle of the century.

There are many concerns around ocean acidification such as the calcifying of corals, mollusks, plankton and algae. The ability of these creatures to build shells or skeletal tissue depends on the abundance of the carbonate ion and for many organisms’ calcification declines with increased acidification. Reduced biodiversity, already an issue with other types of pollution and massive overfishing, is guaranteed with ocean acidification. Other problems include reduced survival, growth rates and development and changes to the physiological functions of marine organisms.