We have some good news this week about the extent of the Antarctica ozone layer. It appears that it seems to be decreasing. The increase in carbon dioxide levels has pushed the greenhouse gases to a record level 2013,. The Antarctic ozone hole reached its peak on 11 September, say scientists. This year’s hole was 9.2 million square miles (24.1m sq km), which is about the same size as the whole of North America. According to scientists from NOAA (National Oceanic and Atmospheric Administration) and NASA, the single-day maximum area in 2014 was similar to that in the previous year, when it reached 24m sq km (9.3m sq m). Ozone concentrations above Antarctica on Sept. 11 and Sept. 30, 2014. (Image: NASA) The Antarctic ozone hole’s largest ever recorded size was 11.5m sq m (29.9m sq km) on 9 September, 2000. The ozone hole 2014 in the Antarctic was less than average for the 2006 time period and comparable to the dimensions in 2010, 2012 and 2013.. The Antarctic ozone hole forms and expands in August and September, ever since higher atmospheric levels of chlorine increased in the 1980s. The ozone layer protects us The ozone layer, about 6.2 miles (10 km) up in the Earth’s atmosphere, which contains high concentration of ozone (03), absorbs most of the ultraviolet radiation from the Sun. The radiation may cause skin cancer or damage to plants. 1987, The Montreal Protocol agreement regulates ozone-depleting chemicals, like bromine-containing halons or chlorine-containing chlorofluorocarbons. These substances were found in Antarctica at a lower level than the 2000 peak. Paul A. Newman is NASA’s chief scientist for atmospherics. He stated that “Year to year weather variability significantly impacts Antarctica’s ozone.” Higher stratospheric temperatures could reduce ozone loss. We see a smaller ozone hole than we did in the early -1990s. And we know that the chlorine levels have been decreasing. Researchers currently try to figure out whether the trend of the ozone holes over the last ten years has been due to temperature rises or chlorine drops. An increase in Antarctica’s stratospheric temperatures would decrease the size of this ozone hole. Both satellite and ground-based measurements show that the chlorine level is falling. However, stratospheric temperatures for this region can be less reliable in determining long-term trends. Researchers also found that the minimum thickness of the ozone layer in 2014 was 114 Dobson units on Sept 30, compared to 250 to 350 Dobson units in the 1960s. NASA wrote: “Over the last 50 years satellite and ground-based records over Antarctica show ozone column amounts ranging from 100 to 400 Dobson units, which translates to about 1 millimeter (1/25 inch) to 5 millimeters (1/6 inch) of ozone in a layer if all of the ozone were brought down to the surface.” Surge in carbon dioxide concentrations A significant rise in CO2 (carbon dioxide) levels pushed up greenhouse gas concentrations in the atmosphere to a new record high in 2013, according to the annual Greenhouse Gas Bulletin issued by the World Meteorological Organization (WMO). According to the WMO, there’s a need for urgent action to prevent the destruction caused by climate change. According to the Bulletin, between 1990 and 2013 there was a 34% rise in radiative forcing – the warming effect of our climate – due to long-lived greenhouse gases such as nitrous oxide, CO2 and methane. Atmospheric CO2 concentrations in 2013 were 142% higher than in 1750, before the industrial revolution, while those of nitrous oxide and methane were 121% and 253% higher respectively. The global average CO2 mole fraction. Image: www.wmo.int. The WMO stated that the CO2 level rose more between 2012 and 2013 than any year since 1984.. This could have been due to a decrease in CO2 intake by Earth’s biosphere and steadily increasing CO2 emissions. Michel Jarraud (WMO Secretary General) stated that “We have no doubts about the fact that our climate and weather are changing rapidly due to human activity such as burning fossil fuels.” The Greenhouse Gas Bulletin shows that, far from falling, the concentration of carbon dioxide in the atmosphere actually increased last year at the fastest rate for nearly 30 years.” “We must reverse this trend by cutting emissions of CO2 and other greenhouse gases across the board. It is now too late. We are running out of time. It is impossible to change the laws of physics. “The Greenhouse Gas Bulletin offers a scientific basis for decision-making.” “NASA Video: Say goodbye to large Ozone Holes
