Bogs may have helped global warming

A new UCLA study suggests the rapid growth of a huge northern
bog complex may have helped activate global warming around the time
of the ice age. The study may provide insight into current concerns
about the impact of global warming on the planet.

Peat bogs, which are masses of organic matter such as leaves and
plants, cause plant material to decay without oxygen, and as a
result release methane gas into the atmosphere. Peat bogs also play
a role in the exchange of carbon dioxide, another greenhouse
gas.

The findings not only dispel previous assumptions of bogs, but
also reveal the environment’s potential to change drastically
over a short period of time.

“Northern bogs are not only older than we had previously
thought, but they developed really quickly,” said Dave
Beilman, a researcher in the UCLA geography department and study
co-author.

The scientists of the study believe the gases released by the
bogs may have contributed to global warming that led to the melting
of the ice glaciers during the ice age about 11,000 years ago.

“This study shows that these kinds of northern bog
environments have played a large part in greenhouse gas
dynamics,” Beilman said.

The greenhouse effect is the process in which the absorption of
radiation by an atmosphere warms a planet.

“Gases in the atmosphere trap radiation that would
otherwise get out of the atmosphere and cool the Earth,” said
David Neelin, a professor in the department of atmospheric and
oceanic sciences.

One of the most important of these gases is carbon dioxide,
which can be emitted by human activities including the burning of
fossil fuels such as oil and coal, he said.

Through studies of trapped air bubbles in the arctic ice, the
concentration of carbon dioxide over thousands of years can be
measured and a recent increase in carbon dioxide can be observed,
Neelin added.

“Greenhouse gases all interfere in the Earth energy budget
in a way that tends to warm the planet as a whole because (heat)
… is less easily able to get to space and is trapped in the
atmosphere,” Neelin said.

But some experts say current human activities as well as
agricultural and industrial by-products are contributing to global
warming.

Yongwei Sheng, a UCLA assistant professor of geography who was
on the team that led the study, said human and physical factors
interact together to cause global warming.

“The human factors release carbon dioxide into the
atmosphere, increasing the temperature in different areas of the
world. … In the arctic, snow caps, which reflect energy, will
melt. As a result, more energy will be absorbed (into the
ground),” he said.

Depending on how hot and dry or cool the peat lands are, carbon
dioxide can either be taken up or released, Beilman said.

Consequently, these greenhouse gases can lead to the warming of
the Earth.

“Once we have these greenhouses accumulated in the
atmosphere it is something like a layer of glass ““ solar
radiation passes through and the radiation cannot get out from
there. So the heat accumulates, increasing the temperature,”
Sheng said.

Methane would be released at a higher rate if temperatures
increase, he added.

But scientists are unsure of whether these masses of organic
material pose a significant threat.

“The million-dollar question is whether these bogs will
exacerbate global warming,” Bielman said. “They have a
dual role in greenhouse gas dynamics; on one hand, they exchange
carbon dioxide with the atmosphere; on the other hand, they are the
single largest natural source of methane (emission).”

The study also exposed the lack of knowledge of the arctic
environment, where a third of the world’s soil carbon is
stored in the bogs, he said.

UCLA scientists have been studying the arctic region for over 30
years and have found that more than 100 arctic lakes have
disappeared, Sheng said.

“The reason is not due to evaporation. … These lakes
sank into the soil because the lake bed (made of permafrost) is no
longer solid because of global warming,” he said.

“Our conclusion was that if the arctic warming trend
continues we’re going to see more lakes disappear and that
will affect a lot of species,” he added.

Scientists remain unsure as to whether the temperature will
increase high enough to kill off species in the next century.

However, people can personally help decrease their contribution
to the greenhouse effect, for instance, by reducing their energy
use with driving a small or hybrid car, not traveling more than
they need to, turning off their lights, and not using air
conditioning unless necessary, Neelin said.