The researchers said carbon dioxide measurements at the Mauna Loa observatory in Hawaii are projected to climb by a record 3.1 parts per million this year, from an annual average of 2.1 parts per million, because of the cyclical El Niño weather event in the Pacific, reported The Guardian. But nonetheless, the long-term trend is steadily upward because humans are putting more carbon dioxide into the atmosphere than plants and other natural “sinks” can pull back out again.
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“This warms and dries tropical ecosystems, reducing their uptake of carbon, and exacerbating forest fires”.
In Nature Climate Change, the researchers, headed by Richard Betts of the UK Met Office’s Hadley Center, wrote that their prediction has backed the suggestion that the Mauna Loa record isn’t ever going to show Carbon dioxide concentrations under the symbolic 400 ppm again within lifetime.
On Monday, scientists who measure and predict greenhouse gases’ concentrations in the atmosphere said that we could have passed a main turning point.
“We have said goodbye to measurements below 400 ppm at Mauna Loa”, he added.
Last November, the Met Office predicted that mean concentrations of atmospheric Carbon dioxide in May 2016 would reach 407.57ppm, with a 0.5ppm margin of error.
What the new study suggests is that those days are over – carbon dioxide will never fall below 400 ppm this year, nor next, nor the next.
To avoid the most dire implications of global warming as projected by the vast majority of scientists, the United Nations’ Intergovernmental Panel on Climate Change has warned against allowing concentration of carbon dioxide to exceed 450 ppm.
The surge in Carbon dioxide levels will be larger than during the last big El Niño in 1997/98, because manmade emissions have increased by 25% since then, boosting the phenomenon’s strength. Starting as brief excursions, the annual average concentration at Mauna Loa was over 400 parts per million, last year, first time ever. “But I do think that these numbers are important for awareness, really…. It’s just an interesting milestone that reminds us of our ongoing influence on the climate system”. Researchers suggest they should start to decline soon, according to the season cycle, where it reaches its peak during May and falls off slightly during September.
CO2 at Mauna Loa is recorded by two independent groups.
Because CO2 is a very long-lived greenhouse gas, it will continue to record high levels in the atmosphere each year, and even if we can find a way to reduce emissions, the levels will not likely drop back below 400 ppm for quite some time.
“In the longer term, a reduction in (carbon dioxide) concentration would require substantial and sustained cuts in anthropogenic emissions to near zero”, said the study’s authors.
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However, the current 400 ppm level is not unprecedented in the Earth’s history.
