Climate Change in the Arctic - The Changing Arctic Environment: The Arctic Messenger - page 289

The answer is an emphatic “Yes”, providing they remember that no effort should be
spared to address the CO 2 issue before we completely run out of time. The warming ef-
fect of SLCFs is short lived because they only survive in the atmosphere for a few days or
weeks or, at most, a few decades. Therefore, we should see beneficial effects much faster
if we can reduce their emissions. To give an idea of the opportunity posed by the prospect
of actions on SLCFs, it has been estimated that they may account for about 30-40% of the
anthropogenic warming so far experienced. According to UNEP, firm action on SLCFs has
the potential to reduce global warming between 2012 and 2040 by as much as 0.5°C. Sub-
stances falling under the SLCF umbrella include HFCs, tropospheric ozone, BC and meth-
ane. What can we say about them?
Ozone-depletingsubstancesandsomeoftheirreplacementsarealsoGHGs.Today,we
are particularly concerned about one family of these substances: HFCs. They first entered
our everyday lives as replacements for CFCs, the substances implicated in the mid-1970s
in stratospheric ozone depletion. Some HFCs are capable of very aggressive radiative for-
cing. As an example, HFC-134a - the most widely used of these compounds - has a GWP
of 1,300 and has an atmospheric lifetime of 13.8 years. Remember that on the same scale,
CO 2 has a GWP of 1. HFC emissions in many countries are the fastest-growing contribut-
ors to global warming. They are growing globally at 10-15% per year. Alone, they could
sabotage global efforts to halt acute climate change by overwhelming the effect of other
reductions of GHG emissions now anticipated under the UNFCCC process until 2050. For-
tuitously, the Montreal Protocol has been tasked not only with controlling ozone-depleting
substances but also with addressing any “adverse effects” arising from their elimination.
The negative contribution to global warming arising from using HFCs as alternatives to
otherozone-depletingsubstancescanobviouslybeconsideredan“adverseeffect”.Bysum-
mer 2012, 108 countries had come out in favour of action against HFCs under the Montreal
Protocol. The Rio+20 Conference in 2012 gave cause for great optimism (but as we will
see, the prize seems as elusive as ever). One of the final declaration documents states: “We
recognize that the phase-out of ozone depleting substances is resulting in a rapid increase