Earth saw its largest annual
spike in atmospheric carbon dioxide concentrations on record in 2015, according
to new data released by the National Oceanic and Atmospheric Administration
(NOAA).
The
increase is significant because it demonstrates the continued march toward
higher levels of global warming pollutants in the atmosphere. Those
increasingly higher levels are helping to destabilize parts of Antarctica and
Greenland, raise sea levels around the world, and cause more frequent and
intense heat waves in many regions.
It is
a sobering milestone too, since countries are working more diligently than ever
to cut emissions of planet-warming greenhouse gases, but the atmosphere is not
yet seeing the results.
According
to NOAA, carbon dioxide measurements taken at the Mauna Loa Observatory in
Hawaii show that carbon dioxide concentrations jumped by 3.05 parts per
million (ppm) during 2015, the largest year-to-year increase in 56 years of
research.
Data
stretching back at least 800,000 years shows that carbon dioxide levels are now
higher than at any other time in human history.
In
another first, NOAA found that 2015 was the fourth straight year in which
carbon dioxide concentrations grew by more than 2 ppm, according to Pieter
Tans, who leads NOAA's Global Greenhouse Gas Reference Network.
“Carbon
dioxide levels are increasing faster than they have in hundreds of thousands of
years,” Tans said in a press release. “It’s explosive compared to natural
processes.”
In
February 2016, the average global atmospheric carbon dioxide level stood
at 402.59 ppm. This is a dramatic increase from preindustrial times, when
atmospheric carbon dioxide levels averaged about 280 ppm.
The
world is currently on course to see carbon dioxide levels push past 450 to 500
parts per million by the end of the current century, unless emissions of
greenhouse gases from burning fossil fuels are cut dramatically during the next
two decades.
A
single molecule of carbon dioxide can remain in the atmosphere for as long as
1,000 years, ensuring that global warming will continue for generations to
come.
According
to Tans, the current rate of increase in carbon dioxide levels is 200 times
faster than the last time the planet saw such a sustained increase, which was
between 17,000 and 11,000 years ago, when there was an 80 ppm increase during
that timespan.
The
jump in carbon dioxide levels this year beat the old record, set in 1997-98.
Both years featured strong El NiƱo events in the tropical Pacific, which tend
to speed up the release of carbon dioxide as trees and other carbon-absorbing
systems adjust to wild swings in weather patterns.
However,
the long-term increase in carbon dioxide emissions is mainly due to the burning
of fossil fuels such as coal, oil and natural gas.
The
carbon dioxide concentration record contrasts with the recent trend in global
annual emissions of greenhouse gases, which may have stalled or fallen slightly in 2015 compared to previous years.
However, it would take a much more significant drop in emissions — all the way
to zero or so-called "negative emissions," in which the Earth absorbs
more carbon dioxide than people emit, in order to stabilize and then drag down
atmospheric levels over time.
No comments:
Post a Comment