Protecting the Arctic - Environmental Audit Committee Contents
2 The impact of climate change on
6. The Arctic is a diverse region encompassing a
seasonally-changing frozen ocean surrounded by continents where
permafrost and tundra give way to vast expanses of boreal forest.
Climatic conditionstemperature, precipitation, wind speeds
and the prevalence of sea ice in coastal areasvary at similar
latitudes. For instance, average temperatures in January are -6.7°C
in Tromsø, Norway but -28.1°C in Fairbanks, Alaska.
"The extent of snow, ice over water, and the dynamics of
glaciers and ice streams vary greatly over short timescales and
from place to place", whereas "the extent of permafrost
and large ice sheets vary and change over decadal timescales and
7. Distinguishing long-term impacts of climate change
from natural variability requires data from many locations in
the Arctic over many years and careful analysis. There is evidence,
nevertheless, that the Arctic is warming twice as fast as anywhere
else on the planet, with average warming north of 60°N of
1-2°C since the 1960s.
Evidence from lake sediments, tree-rings and ice cores suggest
that temperatures in recent decades have been higher than at any
time in the past 2,000 years.
8. Henry Bellingham MP, the then Foreign and Commonwealth
Office Parliamentary Under Secretary and lead Minister responsible
for the Arctic, told us that the Government believed that climate
change "poses the biggest single threat to the Arctic environment".
The effects of climate change are already being felt in the Arctic,
and "are likely to continue more profoundly than perhaps
anywhere else on Earth".
The ice-cap retreating was not the only consequence of climate
change in the Arctic. The extent and duration of snow cover has
decreased, largely as a result of snow melting earlier in the
has increased by 80% over the last century, with much of the increase
falling as rain. Temperatures
in the permafrost have risen by up to 2°C over the past three
decades. Glaciers are
discharge to the sea has increased, reducing the salinity and
density in the North Atlantic. Ice cover on lakes and rivers is
breaking up earlier than previously observed.
9. The biggest change, however, is in the size of
the Arctic ice-cap. Sea-ice has been declining at least since
satellite records began
and is one of the most serious consequences of global warming.
The rate of decline is currently about 3% per decade for the maximum
winter extent (March) and about 10-12% per decade for the minimum
summer extent (September).
The six lowest September ice extents have occurred in the last
six years, including
September 2012 which was the lowest ice extent on record (Figure
1, page 10).
10. Thelatest biennial Arctic Report Card
notes that "there are now a sufficient number of years of
data to indicate a shift in the Arctic Ocean system since 2006
... characterised by the persistent decline in the thickness and
summer extent of the sea ice cover, and a warmer, fresher upper
in the Arctic was not just as a result of increased CO2 emissions,
but also increases in other greenhouse gasses such as methane
and black carbon aerosols, and a decline in cooling sulphate aerosols.
While most emissions driving climate change in the Arctic do not
primarily originate in the Arctic, changes there will have impacts
for the global climate, giving everyone a clear stake in the Region's
11. Increased precipitation, shorter and warmer winters,
and substantial decreases in snow and ice cover are likely to
persist for centuries.
Even with the most "aggressive mitigation scenarios",
there would still be a significant loss of Arctic sea ice by the
end of the century.
Whereas increasing concentrations of greenhouse gasses are "projected
to contribute to additional Arctic warming of about 4-7°C
over the next 100 years".
Professor Tim Lenton of the University of Exeter told us that
the current situation met the Intergovernmental Panel on Climate
Change's definition of "dangerous change".
Professor Peter Wadhams of the University of Cambridge told us
that all the environmental trends of air temperatures, changes
in the ocean, and changes in the sea-ice were heading in the "same
direction", and that "the direction is very clear: We
are going to get into a ghastly situation for the planet at some
point and whether it is happening next year or it is going to
take a few decades is the only question".
John Nissen of the Arctic Methane Emergency Group linked extreme
weather patterns in recent years to a "decrease in stability
as the Arctic warms relative to the rest of the planet".
A reduction in emissions, however, "would allow ecosystems
and human societies as a whole to adapt more readily, reducing
overall impacts and costs",
and is necessary to limit further global warming and avoid more
severe effects in the Arctic and across the globe.
IMPACT ON UK WEATHER FROM CLIMATE
CHANGE IN THE ARCTIC
12. Climatic change in the Arctic is affecting the
UK's weather. Professor Wadhams told us that the open water left
by the retreating ice in summers could lead to "radically
changed" weather patterns around the northern hemisphere.
Britain was warming more slowly when compared with the rest of
continental Europe as the decrease in the thermo-haline circulation
meant that less heat was being brought to Britain by the Gulf
Lenton told us that the loss of ice around Finland and the North
of Norway in the Barents and Kara Seas in winter in particular
was "correlated with so-called blocking events and the extreme
cold winters in Europe". These changes we would "see
on a seasonal time-scale and can have quite big impacts".
13. The Government's Climate Change Risk Assessment,
published in January 2012, noted a potential benefit in terms
of "shorter shipping routes and reduced transportation costs
due to less Arctic ice" (paragraph 107), but did not note
any specific risks to the UK over the coming years.
Professor Julia Slingo, Chief Scientist at the Met Office, believed
that this may be because the Risk Assessment was built on models
developed in the early part of this decade which did not have
the "sophistication of the Arctic sea-ice modelling that
we have now". Professor Slingo agreed that the depletion
of ice could "plausibly impact on our winter weather, and
lead to colder winters over northern Europe" but it was "only
one of a number of factors, ... it is not a dominant driver of
winter weather, particularly over the UK".
The UK has had a number of years with low rainfall
and Professor Slingo told us that she was concerned that if we
continue to have a sequence of cold winters this could be "damaging,
even with wet summers going alongside them" because the replenishment
of aquifers generally occurs through the winter.
Effects on wildlife
14. The Arctic region is one of the last true wildernesses
on Earth. The impact of humans has been limited to date and unique
ecosystems have developed there with a number of endemic species
such as the polar bear.
Many globally significant populations of animals can be found
in the Arctic, including over half of the world's shorebird species,
80% of goose populations, several million reindeer,
beluga whales and narwhals.
Sea-ice is an important element in the Arctic ecosystem for some
species, from bacteria
and unicellular algae on the underside of the ice to large mammals
such as the polar bear and ringed seals.
15. Half of the marine area of the Arctic is covered
by seasonal ice in winter, turning into open water in the summer.
This drives large migrations,
meaning that a significant proportion of Arctic biodiversity is
shared with other parts of the world, especially the UK.
The cold waters, high in nutrients, attract large numbers of migratory
grey and humpback whales and harp and hooded seals.
15% of the world's migratory bird species spend their breeding
season in the Arctic.
16. Arctic ecosystems appear to be particularly vulnerable
to the effects of climate change,
although they are still poorly understood and long-term data are
sparse. For instance,
of the 19 sub-populations of polar bears, there were only reliable
data to assess the trend in numbers of seven.
The Arctic Council's Biodiversity Assessment, due to be published
in Spring 2013, aims to provide baseline data on Arctic wildlife.
Nevertheless, disappearing sea ice and changing water temperatures
were already "having a profound impact on many species".
A recent Arctic Council assessment found that the impact of climate
change on marine animals and birds was likely to be "profound".
There are fewer polar bears because they are finding it more difficult
to hunt for food in the south of their ranges.
Walruses are also being forced to hunt in deeper water, where
access to food is much more difficult.
Ecosystems would be affected by permafrost degradation, with existing
lakes drained but also new wetlands created.
Herds of reindeer have declined by one-third since the 1990s as
their access to food sources, breeding grounds, and historic migration
routes have been altered.
Precipitation was increasingly falling as rain during the winter,
which created an ice-crust over the snow, affecting grazing animals.
Increased 'greening' of the land is affecting the animals it supports.
Species specifically adapted to the Arctic climate are especially
at risk, including many species of moss and lichens, lemmings,
voles, arctic fox and snowy owl.
Increasing levels of ultraviolet radiation in the Arctic due to
stratospheric ozone depletion is also a risk to wildlife.
The impact of climate change on biodiversity could be magnified
by other factors such as the presence of contaminants, habitat
fragmentation, industrial development and unsustainable harvests.
17. Some Arctic species often have very long lifespans
and slow reproduction rates,
and "relatively simple ecosystem structures and short growing
seasons limit the resilience of the natural environment, and make
environmental recovery harder to achieve".
This makes the Arctic environment "highly sensitive to damage"
of a kind that would be likely to have long-term impacts.
Climate change could cause a mismatch between the timing of reproduction
of certain species and food availability.
18. In the longer term, the composition of Arctic
ecosystems will change. There will be a northward movement of
some species, including some fish.
As the Arctic become ice-free in summers, new species are expected
to take advantage of the high summer light levels in the upper
layers of the oceans.
Migrating invasive species might displace native Arctic inhabitants.
19. A reduction in sea-ice and rising sea levels
could increase coastal erosion as higher waves and storm surges
reach the shore.
Two-thirds of the Arctic coastline is protected by ice, and melting
land-fast ice could lead to rapid erosion.
This will affect people as well as animals. Habitat changes, chemical
pollution, overfishing, land use changes, population increases
and cultural and economic changes are amplifying the impacts of
climate change on the health and wellbeing of Arctic communities.
Many indigenous peoples depend on hunting Arctic mammals, herding
reindeer and fishing, not only for food, but as part of their
cultural and social identity.
Changes in species' ranges and availability present "serious
challenges to human health and food security and possibly the
survival of some cultures".
20. These climate change effects on the Arctic might
be exacerbated and accelerated if 'tipping points' are breachedthese
are points at which rapid changes take place out of proportion
to the amount of climate change driving them as a result of 'positive
could lead to rapid or longer term changes depending on the climate
Some 'tipping points' may be reversible and others may not.
We explore the likelihood of such tipping points below.
THE RETREATING ARCTIC ICE-CAP
21. The Arctic Ocean ice-cap has a seasonal cycle,
reaching its maximum extent in March and minimum extent in September.
Since the 1950s the summer extent of ice has been retreating year
on year, at a rate of 4% per decade.
But since the early 2000s this rate has increased to 10-12%.
The amount of "older, thicker multi-year ice continues to
"modelling indicates that the total area of ice may be more
variable year to year as more areas of ice become susceptible
to melting completely during the summer".
Alongside rising temperatures, there are a number of other factors
forcing this retreat that are still not fully understood, including
climate-driven changes in atmospheric and ocean circulation patterns
and a reduction in summertime cloud levels.
22. The retreating ice-cap represents a potential
tipping point because the heat of sunlight is more readily absorbed
when falling on water than on ice (ice has a higher 'albedo' than
water), causing further warming and further ice retreat in turn.
Professor Wadhams calculated that the open water left by the retreating
ice-cap warms up to 4-5°C during the summer, delaying the
onset of autumn freezing and warming the seabed, helping to melt
Faster wind speeds and bigger waves were also a consequence of
larger stretches of open water, which break the ice up into floes
and increase the melt rate.
The Arctic Methane Emergency Group were concerned that "the
rate of warming of the Arctic could double or even triple, once
the Arctic Ocean is ice-free in September. And it could double
again, once the ocean is ice-free for half the year".
23. Professor Lenton believed that there was some
evidence that sea-ice retreat may have already passed a tipping
point. The last six summers had the six lowest recorded ice extents,
with a "step up in the amplitude of the seasonal cycle of
sea-ice variability", which could "perhaps [be] seen
as passing some kind of tipping point or threshold". But
he recognised that there was also "plenty of argument about
whether there is really a tipping point", depending on whether
a loss of summer ice would prevent ice reforming in winter.
Professor Wadhams told us that once the summer sea-ice disappears
the oceans would warm up and their structure would change to the
point where if the climate cools again it would be difficult for
ice to form again. He did not think that there would be an "oscillation"
back and forth; it would be a "one-way street".
John Nissen of the Arctic Methane Emergency Group believed that
"the imminent collapse of Arctic sea-ice poses a new emergency
situation, ... it threatens an irreversible transition towards
abrupt and catastrophic climate change".
However, the Met Office believed that its modelling suggested
that Arctic sea-ice loss would be "broadly reversible if
the underlying warming were reversed".
24. In recent months, further research results on
the volume (rather than extent) of the ice have added weight to
the possibility of approaching ice-free Arctic summers. Although
the extent of ice had been reliably measured since the 1970s,
the thickness of the ice-cap was more difficult to measure because
it cannot be easily observed from satellites.
Measuring the thickness had been undertaken using submarines,
which had showed that the ice-cap had reduced by about 45% since
the 1970s. The Pan-Arctic
Ice-Ocean Modelling and Assimilation System (PIOMAS), at the University
of Washington, calculated
in 2011 that the volume of ice in Septembers had decreased by
75% since 1979. Professor
Wadhams believed that the data was "held in high regard"
by many experts in the field.
He and John Nissen took issue
with Professor Slingo who, giving evidence in March 2012, told
us that "there is a decline in ice ... but to say we have
lost 75% of the volume is inconsistent with our assessments".
She was looking forward to new measurements from the CryoSat-2
satellite, which she believed would give a better sense of the
thickness of the ice.
25. There were different estimates of when the Arctic
would become ice-free
in summer, depending on what model was employed.
Professor Lenton told us in February that it was "highly
unlikely" that the Arctic could be ice-free in the next few
summers. His "best guess" was "sometime in the
2030s, maybe 2040s".
Professor Wadhams believed that, taking account of the thinning
of the ice-cap, "it is very much quicker, perhaps needing
only 4 years".
He believed that the rate of retreat and thinning had "greatly
exceeded" the predictions of most models, except PIOMAS.
The Arctic Methane Emergency Group's extrapolation of data on
the volume of summer ice from the PIOMAS model, following an exponential
reduction trend-line, suggested that Septembers would be ice-free
26. On the other hand, Professor Slingo told us that
a recently completed Met Office assessment (which we saw in draft
in the course of our inquiry and was subsequently published in
had indicated that the earliest date at which the Arctic would
be ice-free during the summer would be between 2025 and 2030,
and "certainly not in the next few years...".
The climate models on which these predictions are based were "capable
of capturing the observed decline in ice extent", however
they "do not generally show ice loss at the current
rate until later in the 21st century" and "low
ice events", such as observed in 2007 and 2012, were "unusual
in the models, occurring only once in every 100 years". The
Met Office assessment noted that others' projections of a seasonally
ice-free Arctic by as early as 2013 was "based on extrapolating
model output [and] have to be viewed with scepticism". It
noted that there were "plausible mechanisms" for more
rapid change in the Arctic than current models predict, but "further
observations are required to establish if any of these
mechanisms are occurring". The Met Office concluded
that an ongoing assessment of the likelihood of rapid change
was required, taking account of the "constantly developing
Professor Slingo told us that as the Arctic warms and the sea
ice becomes thinner, "you do expect the extent will
become more volatile".
Understanding of "how the Arctic Ocean takes up heat, and
how that then affects the sea ice behaviour" was still being
developed, but she believed that the models used were "capturing
the trend and the volatility quite well", although they would
not capture particular events (such as El Nino) which could drive
Arctic circulation changes.
27. Since our evidence sessions, some preliminary
analysis of data from the CryoSat-2 satellite was broadcast in
August 2012, which
supported predictions that the Arctic would become ice-free during
the summer sooner rather than later. The European Space Agency's
CryoSat-2 satellite was launched in 2010 to monitor the changes
in the thickness of the Arctic sea-ice and the ice sheets on Greenland
Professor Seymour Laxon of the Centre for Polar Observation and
Modellingleading the analysis of the Cryosat-2 datatold
us that preliminary analysis of the Cryosat-2 data combined with
that of NASA's ICESat satellite, showed that between 2003 and
2011 the volume of summer sea ice in October/November had reduced
from ~14,000 to ~7,000 cubic kilometres (a 50% decrease). Averaged
over the period, up to 900 cubic kilometres of summer sea-ice
was lost a year.
He told us that these data "suggest a decrease ... at least
as large as that simulated by PIOMAS, and possibly higher".
The Met Office believed that evidence pointed to weather patterns
having influenced the rapid loss of sea ice over this summer.
The changes in sea-ice volume shown in recent estimates "only
extends over a few years" and was not "representative
of a long term trend".
Although we recognise the Met Office's
and Professor Laxon's concerns about extrapolating trends in volume
loss into the future,
a simple calculation based on this data points to the Arctic becoming
ice-free in the summer within a decade.
28. There is growing evidence that the damaging
effects of climate change are being felt strongly in the Arctic.
The ice-cap is retreating. In September 2012 it had reached its
lowest extent since satellite records began, and new evidence
shows that it is also thinning faster than previously thought.
The general view that the ice-cap is not at risk of a summer collapse
in the next few years may need to be revisited and revised. A
collapse not only threatens the unique ecosystems there, but would
have damaging ramifications for regional and global climate.
29. Permanently frozen ground, or permafrost, covers
10.5 million square kilometres of the Arctic.
Thawing permafroston land or potentially in the shallow
seascould represent a tipping point. 'Positive feedback'
would come from organic matter contained within it decomposing
and generating heat and releasing methanea greenhouse gas
which would drive further permafrost thawing.
Methane is a relatively short-lived greenhouse gas
but has a warming effect 72 times more than CO2 over 20 years.
30. John Nissen of the Arctic Methane Emergency Group
told us that "methane is a real problem and it is never really
addressed". He believed that "because of its potency
as a greenhouse gas, we only need release of 1% of ... the Arctic
potential methanethat is about 35 billion tonnesand
that would triple the current rate of global warming". He
believed that "it is difficult to see how civilisation could
survive such a thing".
31. Professor Lenton told us, however, that from
the Hadley Centre's model their "best estimate is we may
get 0.1°C of extra warming at the end of the century from
the loss of methane from the northern high latitudes".
He believed that the present lack of evidence to the contrary
meant that methane released from permafrost "is not on the
list of tipping elements", but that different regional areas
of permafrost might be at risk at different times.
The Yedoma area of Siberia was a particularly "rich"
store of carbon that could "undergo self-sustaining collapse,
due to an internally generated source of heat released by bio-chemical
decomposition of the carbon, triggering further melting in a runaway
positive feedback", but 9°C of regional warming would
be required to pass such a tipping point.
32. Methane released from permafrost on land requires
bacterial and microbial action, and is sensitive to temperature
rise. Under the
sea, existing stores of methane could be abruptly released.
An increase in methane had been linked to mass extinctions in
the past but,
Professor Lenton told us, that methane release had been over "thousands
and tens of thousands of years".
Professor Wadhams believed that the summer retreat of the ice
from the Arctic continental shelves
was allowing the surface layer of the ocean to warm up and "bringing
temperatures of up to 5°C right down to the seabed".
This was accelerating the melt of offshore permafrost and releasing
methane trapped in methane hydrates (comprising methane water
and ice). Large
plumes of methane were appearing "all over the summer Arctic
shelves" giving "a very big boost to global warming".
John Nissen of AMEG told us that 50 gigatonnes of methane were
trapped in the East Siberian Arctic Shelf, which if released would
raise atmospheric methane levels eleven or twelve times, causing
"abrupt and catastrophic climate change within a few decades".
33. Professor Slingo differentiated between the methane
hydrates in the Arctic shelves and the "deep hydrates that
would take millennial timescales to destabilise". She believed
that based on modelling estimates "we are not looking at
catastrophic releases of methane", although it was "still
very early science". She thought that there was uncertainty
about how far heating of the upper level of the ocean could dissipate
downwards in the water column, and that "there is still a
big debate as to how much the actual continental shelf itself
Apart from one or two regions, observed increases in sea-floor
temperatures had at the most been only about 0.1oC.
She also told us that research indicated that where there was
methane coming out of the continental shelf in those one or two
areas, "there is a general consensus that only a small fraction
of methane, when it is released through this gradual process of
warming of the continental shelf, actually reaches the surface".
John Nissen and Professor Wadhams disputed that view.
The Arctic Methane Emergency Group were also concerned that if
methane hydrate became unstable it could pose a hazard to oil
34. There is a range of views on the rate at which
methane is being released in the Arctic as a result of climate
warming there, and whether and how soon that might constitute
a tipping point. Given its particular potency as a greenhouse
gas, however, there is a potentially serious risk for global climate
change from any significant methane release in the Arctic. We
discuss below whether such risks warrant specific interventions
THE GREENLAND ICE-SHEET
35. Most of Greenland is permanently covered in ice.
Unlike with sea ice, any reduction in the Greenland Ice-sheet
mass contributes directly to global sea levels.
The ice sheet contains approximately 2.85 million cubic kilometres
equivalent to 7 metres of global sea level rise.
Up until the 1990s only a tiny proportion of this overall volume
melted each year, and much of that was compensated for by fresh
snowfall on Greenland.
Recently, however, the rate of ice-sheet loss has accelerated
as a direct result of the warming Arctic climate.
36. Measurements in 2009 show there have been quite
large and rapid changes in surface melting and ice discharge.
Measurements by NASA satellites showed that nearly 97% of the
Greenland ice-sheet surface had thawed at some point during July
2012. The retreat
of the summer sea ice from around Greenland warms up Greenland,
and means that the Greenland ice-sheet melts more rapidly.
The contribution from the Greenland ice-sheet melt now is "about
as great as all the rest of the retreating glaciers in the world
and the current net loss represents enough water to supply more
than one billion city-dwellers.
Professor Wadhams believed that this will mean that "over
the next century the rise in global sea levels will probably be
greater than predicted by [the Intergovernmental Panel on Climate
Change] ... quite a lot more than one metre instead of less than
37. Professor Lenton pointed out that predictions
of what degree of future global warming would result in an irreversible
retreat of the ice-sheet ranged from between 0.7°C and 6°C.
There could be "multiple stable states" for the ice-sheet
volume and "multiple tipping points", starting with
a retreat of the ice-sheet onto the land, but there was insufficient
information to prove that this process was already underway.
Other research indicated that the original ice sheet volume could
only be regained if the losses were no greater than 10-20%.
38. Satellite images showed an area twice the size
of Manhattan had broken away from the Petermann glacier in July
2012. A recent
Danish research project suggests that the ice-sheet may be melting
in "spurts", making global sea rise difficult to predict.
More generally, the interactions between ocean, snow, ice and
the atmosphere are not fully understood, making predictions in
this area difficult.
THE THERMO-HALINE CIRCULATION
39. The Atlantic thermo-haline ocean circulation
acts as a conveyor belt bringing warm water to the Arctic and
transporting cooler water back to the tropics. It is composed
of wind-driven surface currents (in this case the Gulf Stream)
and deep ocean circulations. In the Arctic, water sinks in the
Greenland and Labrador Seas and then flows southwards.
40. Some evidence points to additional freshwater
from ice-melt reducing the salinity of the Arctic Ocean
which, coupled with temperature changes, is slowing down the circulation.
The Greenland Sea sinking current had "diminished very significantly"
in the last 10 years because ice-formation had stopped there (ice-formation was needed to enhance the density of the
[remaining] water and help it sink).
Professor Wadhams told us that previously a "see-saw"
was evident, whereby if the Labrador Sea convection got weaker,
the Greenland Sea convection got stronger, and vice-versa. However,
he told us that there was some evidence that there was a weakening
of both sinks, leading to the whole circulation weakening.
A change in circulation patterns could represent a tipping point,
resulting in changed regional and global climate.
41. However, any change to the circulation "was
a slow process [and was] not going to change things rapidly".
Professor Lenton explained that currents could shut off potentially
from one year to the next, but "to truly see the consequences
climatically play out, ... much longer time scales are involved,
up to centuries".
Professor Slingo did not think that there would be "very
large changes" in the thermo-haline circulation "within
the next century".
Professor Lenton believed that such predictions were based on
assumptions that the circulation patterns were stable, but that
these might need to be revisited to reflect recent work suggesting
that there may be "multiple states" for the Atlantic
circulation. He believed that rather than a total collapse of
the thermo-haline circulation, a relatively near-term collapse
of the Labrador Sea convection could result in the overall weakening
of the wider regional thermo-haline circulation.
42. John Nissen believed that a switching off the
thermo-haline circulation might reduce warm waters flowing into
the Arctic, but he accepted that this would be a disaster for
the UK's climate.
Professor Wadhams told us that this would not be sufficient on
its own to "bring back the ice".
43. The lengthening of the snow-free season is encouraging
shrub growth in the tundra, and also 'greening' of the boreal
forest further south.
Whilst a greater amount of vegetation is likely to increase carbon
uptake from the atmosphere, the reduced reflectivity of the land
surface (albedo) is likely to outweigh this, causing further warming.
Some models project that by 2100 the tree-line will have advanced
north by as much as 500 km, resulting in a loss of 51% of the
However, Professor Lenton did not expect this to be a tipping
EARLY WARNING ON TIPPING POINTS
44. Although there is some information on the likelihood
of crossing some Arctic climate tipping points, "substantial
and there is "still a long way to go in correctly identifying
tipping points and assessing their proximity".
Professor Lenton told us that it would be difficult to develop
a suite of early warning signs for changes in the Arctic because
there was inadequate monitoring.
Professor Wadhams told us that although "there are disagreements
about the speed at which changes are happening and will happen",
the "direction of them I think everybody is agreed on".
Similarly, Professor Lenton believed there was consensus that
climate forcing is going to trigger some tipping points within
the next century, and he could not rule out that some tipping
points may already have been crossed.
45. In the absence of urgent action on climate
change, there may be a number of tipping points in climate-driven
systems in the Arctic, which threaten to rapidly escalate the
danger for the whole planet. A collapse of summer sea-ice, increased
methane emissions from thawing permafrost, runaway melting of
the Greenland ice-sheet, and a collapse of the thermo-haline circulation,
may all be approaching in the Arctic and will have disastrous
consequences for global climate and sea levels. These together
comprise a wake-up call to reinvigorate efforts to tackle climate
change. A lack of consensus on precisely how fast any tipping
points are approaching in the Arctic should not be used as an
argument for inaction; rather it demonstrates the need for continued
and sustained research to underpin further action. The UK makes
an essential contribution to Arctic science, which we discuss
in Part 4, and we look to the Government to continue supporting
Arctic science as a key component of its work on climate change.
46. We examined potential interventions that might
yield positive outcomes on Arctic climate change in the near term'geo-engineering'
and reducing black carbon.
47. The Arctic Methane Emergency Group called for
urgent intervention by governments to avoid tipping points being
that there was "nothing in nature that can come to our help",
the Group called on governments to "intervene by cooling
the Arctic, principally by using geo-engineering techniques; ...
[these] techniques have natural analogues which suggest that they
should be safe and effective ... if their deployment [avoided]
They called for the urgent application of a combination of three
geo-engineering technologies: spraying aerosols into the stratosphere
to reflect sunlight away, cloud brightening using salt-spray also
to increase reflection, and cloud removal to allow heat radiation
into space. They also called for the use of methane capture technologies
such as 'methane mats'.
48. There was some differences of view in the evidence
we received about whether geo-engineering in principle was a credible
long-term solution. Professor Wadhams saw geo-engineering as a
"sticking plaster" until the forcing of climate warming
is tackled, and
John Nissen believed that the costs would be "hundreds of
millions rather than many billions per year".
On the other hand, if such applications were subsequently stopped,
the planet would warm up more quickly to where it would have been
without geo-engineering, rather than the gradual warming otherwise
Lenton told us that "if you go down that path, you are committing
not just the next generation but tens of generations potentially
to keep doing that". He believed that it was important that
economic modelling of geo-engineering costs included the "possible
damages or risk factors" and a "critical look at those
very few existing studies as to whether they have really quantified
49. There was consensus that even if geo-engineering
techniques could be used, they first required further development
and were not ready for immediate deployment.
Professor John Latham ofUniversity Corporation for Atmospheric
Research, Boulder, USA and colleagues believed that as "key
climate processes remain poorly understood, existing models are
unable to provide a reliable means of quantifying the magnitude
of changes that may occur".
Professor Lenton told us that advocates of geo-engineering techniques
who suggest "meddling with Arctic cloud cover", do not
necessarily realise that during the dark Arctic winter clouds
generally warmed rather than cooled the atmosphere.
Overall, due diligence was needed to understand all the consequences
of such techniques,
including impacts on rainfall,weather patterns
and reduced incoming sunlight.
Professor Latham and colleagues believed that any geo-engineering
scheme "needs to have its concepts rigorously challenged
and then undergo rigorous, peer reviewed testing and scrutiny
before any consideration of its use takes place".
50. Geo-engineering techniques for the Arctic
at present do not offer a credible long-term solution for tackling
climate change. Further research is needed to understand how such
techniques work and their wider impacts on climate systems. In
the meantime, therefore, we remain unconvinced that using 'technical
fixes' is the right approach and efforts should not be diverted
from tackling the fundamental drivers of global climate change.
51. A more realistic and lower-risk intervention
would be to tackle black carbon. Black carbon is a component of
soot which arises from the incomplete combustion of fossil fuels
and organic matter.
Major sources of black carbon include diesel engines, commercial
and domestic burning, domestic wood and biomass burning, and land
or agricultural burning.
Soot from fires in boreal forest fires, which have increased in
frequency, could also be a source.
The depositing of these microscopic dark particles onto snow and
ice reduces the albedo effect (allowing the absorption of more
is having a greater effect in the Arctic than black particles
in the atmosphere.
52. Professor Lenton told us that there was a lack
of an "evidence base to tie down how strong the black carbon
warming effects in the Arctic region are" but he thought
that it made a "significant contribution".
Professor Wadhams thought that black carbon was probably the third
biggest contributor to warming in the Arctic, after CO2 and methane.
It had been estimated that a steep increase in black carbon and
a decline in reflective sulphates had together accounted for up
to 70% of Arctic warming since 1976.
Research was continuing to establish the sources of black carbon,
but it was estimated that more than half the black carbon that
reaches the Arctic originated in the EU.
Ed Dearnley from ClientEarth told us that the greatest potential
for black carbon reductions was from China, Russia and the EU.
53. In contrast to CO2 and methane, black carbon
has a very short atmospheric lifespan and ClientEarth believed
that reducing emissions of black carbon has the "potential
to deliver rapid climate change mitigation". It believed
that "reducing black carbon and other short-lived climate
'forcers' could reduce regional warming in the Arctic by approximately
two-thirds over the next 30 years".
Professor Lenton believed a good case for tackling black carbon
could be made based on the health benefits alone, but tackling
black carbon could make a "measurable difference" to
the Arctic against a lack of progress on the "big CO2 problem".
54. ClientEarth suggested a number of actions that
the Government should take to tackle black carbon, including strengthening
of the Gothenburg Protocol.
The Protocol sets national emissions ceilings for a variety of
Protocol was revised in 2012 and for the first time introduced
an emissions reduction target for fine particulate matter ('PM2.5').
The UK agreed a PM2.5 reduction target of approximately 30% by
2020 (from a 2005 baseline), which Defra believed was "substantial".
Defra told us that as black carbon is a component of particulate
matter, reductions in emissions of PM2.5 will also reduce black
targets in the UK and EU for particulate matter could also contribute
themselves to reducing black carbon emissions. Alan Andrews of
ClientEarth told us that "we just need to make sure [air
pollution legislation] is enforced properly".
We examined the Government's efforts to improve air quality in
a 2011 Report, and found that the UK is still failing to meet
European targets for safe air pollution limits across many parts
of the country and that the step change called for has not happened.
We recommended, among other things, that a Ministerial Group is
set up to oversee delivery of a new cross government air quality
strategy, a national framework of low emissions zones is set up,
and a public awareness campaign is launched.
55. There are significant risks of increased depositing
of black carbon on Arctic snow and ice as new commercial opportunities
in shipping, resource extraction and other industrial activities
opened up. ClientEarth
believed that international shipping was a "comparatively
poorly regulated sector for particulate matter emissions"
and that black carbon and other emissions from shipping in the
Arctic "may increase by as much as a factor of two or three
by 2050 unless control measures are put in place".
Alan Andrews told us that it was difficult to get agreement at
the International Maritime Organization on environmental protection
as it had a "huge number of competing interests" from
nations with very large shipping interests.
There is no international regulation of greenhouse gasses from
ships and shipping is not included within the EU Emissions Trading
System. In January 2012 the EU launched a consultation to gather
ideas on options to reduce emissions from shipping,
in line with its commitment to include emissions from shipping
within the existing EU reduction commitment if international action
was not agreed.
The risks to ecosystems from the effects of Arctic warming
and potential climate tipping points that we have discussed
in this Part, together with the additional risks from energy
and shipping development which we discuss in Part 3, make
it imperative that any readily available opportunity to make a
difference is grasped. Tackling emissions from shipping is such
an opportunity, and the Government must engage positively with
the EU's efforts to look at options for doing this. We examine
in Part 4 the scope for the Government to influence other countries'
efforts to reduce black carbon.