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How is climate change affecting the Arctic Ocean?
Global warming is causing Arctic ice to melt –
ice reflects sunlight, while water absorbs it. When the
Arctic ice melts, the oceans around it absorb more sunlight and heat
up, making the world warmer as a result.
Why is Arctic sea ice melting?
As water and air temperatures rise each summer near
the Poles, some sea ice melts. Differences in geography and climate
cause Antarctic sea ice to melt more completely in the summer than
Arctic sea ice. ... For ice to thicken, the ocean must lose
heat to the atmosphere. But the ice also insulates the ocean
like a blanket.
Global warming is
causing Arctic ice to melt – ice reflects sunlight, while
water absorbs it.
For ice to thicken, the
ocean must lose heat to the atmosphere.
Solar Radiation Management (sun dimming) uses
various methods for reflecting the sun away from the earth .[Picture
above taken May 12, 2017 by jt]
Does global warming cause ice age?
Although loosely based on science, the deep-freeze
scenario is wildly implausible and scientists queued up to pour cold
water on it. “It is safe to say that global warming will not
lead to the onset of a new ice age,” two distinguished
climate scientists wrote in the journal Science. Mar 14, 2018
In 1959 there was discussions about deflecting
the warm waters of the Japanese current by building a barrier near
Bering Strait, thus sending part of the current into the Arctic
basin and warming up polar regions to open them for habitation.
Scientists pointed out that until meteorological knowledge of
the natural controls of weather and climate was more adequate it
would be folly to undertake such a major change in ocean currents
and climate because present knowledge indicated that warming of the
Arctic ocean would set off a sequence of changes that would bring on
another ice age.
In the South China Sea (SCS) between 2013 and 2017,
China built 3,200 acres of new land, Vietnam built 120 acres of new
land, and Taiwan built eight acres of new land. Given this level of
activity in the SCS and the fact that environmental alterations,it's
natural to ask: what impact do these activities have on
climate change?
Geoengineering refers to a set of emerging
technologies that could manipulate the environment and partially
offset some of the impacts of climate change. Solar geoengineering
in particular could not be a replacement for reducing emissions
(mitigation) or coping with a changing climate (adaptation); yet, it
could supplement these efforts.
GEOENGINEERING IS CONVENTIONALLY SPLIT INTO TWO BROAD CATEGORIES:
THE FIRST IS CARBON GEOENGINEERING, OFTEN ALSO CALLED CARBON DIOXIDE
REMOVAL (CDR). THE OTHER IS SOLAR GEOENGINEERING, OFTEN ALSO CALLED
SOLAR RADIATION MANAGEMENT (SRM), ALBEDO MODIFICATION, OR SUNLIGHT
REFLECTION. THERE ARE LARGE DIFFERENCES.
Carbon geoengineering seeks to remove carbon dioxide from the
atmosphere, which would address the root cause of climate change —
the accumulation of carbon dioxide in the atmosphere. In the chain
from emissions to concentrations to temperatures to impacts, it
breaks the link from emissions to concentrations.
Solar geoengineering seeks to reflect a small fraction of sunlight
back into space or increase the amount of solar radiation that
escapes back into space to cool the planet. In contrast to carbon
geoengineering, solar geoengineering does not address the root cause
of climate change. It instead aims to break the link from
concentrations to temperatures, thereby reducing some climate
damages.
am
SOLAR GEOENGINEERING
There are several proposed solar geoengineering technologies. These
include marine cloud brightening, cirrus cloud thinning, space-based
techniques, and stratospheric aerosol scattering, amongst others.
Marine cloud brightening would attempt to brighten marine clouds to
reflect more sunlight back into space.
Cirrus cloud thinning would attempt to reduce the thin,
high-altitude cirrus clouds to emit more long-wave radiation from
the earth to space.
Space-based technologies would attempt to reflect a small fraction
of sunlight away from the earth by positioning sun shields in space.
Lastly, stratospheric aerosol scattering would introduce tiny
reflective particles, such as sulfate aerosols or perhaps calcium
carbonate, into the upper atmosphere, where they could scatter a
small fraction of sunlight back into space.
More information can be found on the Technology Factsheet: Solar
Geoengineering from the Harvard Belfer Center and Center for
Research on Computation and Society (CRCS).
am
SOLAR GEOENGINEERING BENEFITS AND RISKS
Climate models have consistently shown that solar geoengineering,
when used in moderation and combined with emissions cuts, has the
potential to reduce climate changes around the globe. For example,
it could reduce climate impacts such as extreme temperatures,
changes in water availability, and intensity of tropical storms.
However, any benefits come with novel risks and significant
uncertainty. For example, while the latest science might show some
benefits globally, local impacts could vary more widely. There are a
lot of other scientific uncertainties that are not yet well
understood, not least the enormous governance challenges.
Also, solar geoengineering (largely) does not address ocean
acidification. Every year, the ocean absorbs about one-quarter of
the carbon dioxide we emit into the atmosphere, changing the
chemistry of the oceans and harming marine ecosystems. Given that
solar geoengineering would not remove carbon dioxide from the
atmosphere directly, but rather reflect sunlight back to space, it
could do little to address this serious problem except via carbon
cycle feedbacks, the process through which additional carbon is
emitted into the atmosphere upon additional warming.
That said, solar geoengineering could reduce rising temperatures,
offsetting many impacts on the oceans. For example, by reducing sea
surface temperatures, it could reduce the risk of coral bleaching
events and help to maintain conditions favorable for coral reefs (as
the damage to coral reefs is largely caused by rising sea surface
temperatures, followed by intensifying ocean acidification). Solar
geoengineering could also reduce poleward shifts in species ranges,
which has been posing serious risks to tropical fisheries. And it
could lessen the amount of sea-ice loss, which could reduce the
impacts on high-latitude ecosystems and climate, and help to limit
changes in ocean circulation and glacier melt.
In any case, solar geoengineering could not be a substitute for
cutting carbon dioxide pollution. It could only be a potential
supplement.
am
SOLAR GEOENGINEERING RESEARCH
Research could reduce uncertainty about the technology’s potential
benefits and risks, but, for decades, research in solar
geoengineering has been limited. This has been in part because of a
fear that it could lesson efforts to cut emissions. There have also
been concerns pertaining to its ethics, governance, and potential
impacts to the climate system. Recently the U.S. National Academy of
Sciences and major environmental groups such as the Environmental
Defense Fund and the Natural Resources Defense Council have begun to
support careful research. The U.S. also published the Climate
Science Special Report, which discussed geoengineering and called
for further research. The report was a key part of the Fourth
National Climate Assessment, which the U.S. Global Change Research
Program (USGCRP) oversaw.
Researchers at Harvard
SOLAR GEOENGINEERING RESEARCH AT HARVARD
Please explore these pages for our latest events, research projects,
publications, and how to get involved.
ff
Harvard University Center for the Environment
26 Oxford Street
Cambridge, MA 02138
https://geoengineering.environment.harvard.edu/geoengineering
How deep is Harvard into
geoengineering? We'll see...
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