The Long and the Short of It - The Changing Arctic Environment: The Arctic Messenger - page 347

to be somewhere after 1938 and before 1988. For world political leaders, I think it would
be reasonable to pick 1992, when the United Nations Framework Convention on Climate
Change (UNFCCC) was opened for signature.
With every IPCC assessment and with every new issue of the most influential sci-
entific journals, the reality of climate change and its attribution to GHG emissions become
more clearly defined. Here is an example. As I was completing the penultimate draft of this
topic in December 2013, James Overland and colleagues published a paper in the journ-
al Earth's Future . It took a new look at predicting the scale of temperature projections for
the Arctic in the second half of the twenty-first century using RCP scenarios. They chose
the RCP8.5 scenario to represent rising emissions, resulting in 8.5 W/m 2 (about 1,370 ppm
CO 2 ) by 2100 and chose RCP4.5 to represent an emission trajectory that (through the ap-
plication of mitigation) achieves stabilization at 4.5 W/m 2 (about 650 ppm CO 2 ) by about
2060. Using global circulation models, the authors found that the RCP8.5 scenario (busi-
ness as usual) leads in 2100 to an Arctic-wide “increase of +13°C in late fall and +5°C in
late spring”. In contrast, the RCP4.5 mitigation scenario leads in 2100 to an Arctic-wide
“increase of +7°C in late fall and +3°C in late spring”. The projected increases are relat-
ive to a 1981-2005 baseline. This sounds alarmingly similar to the personal communica-
tion from Bob Corell mentioned in the climate chapter under the section “Sea Level Rise
in the Arctic and Around the Planet.” Even if we can succeed in ignoring the impacts of
an Arctic-wide temperature increase on the scale indicated by these studies, can we ignore
the impact on sea level elsewhere? However one looks at it, results such as these plead for
swift and effective mitigation action.
Reaction:
The two classes of reaction we may expect governments to take are actions to alleviate
the expected impacts of climate change over a given time frame. An example of the first
would be to increase the protection of vulnerable coastal areas and cities to rising sea
levels and storm surges. This is called adaptation and its implementation is mainly a na-
tional or subnational responsibility. The second is to attack the root cause of the issue,