Vast Costs of Arctic Change

Home , Greenland ice sheet, Ice sheet

COMMENT EVOLUTION The man who linked SPACE Mountain guardian INNOVATION Do Nobel laureates OBITUARY Jerome Karle, crystal ecological isolation and asks astronomers to eat more chocolate than the structure mathematician, speciation p.404 show respect p.407 foot soldiers of science? p.409 remembered p.410 B&C ALEXANDER/ARCTICPHOTO

Pipes transport oil from rigs on Endicott Island in Alaska. Vast costs of Arctic change Methane released by melting permafrost will have global impacts that must be better modelled, say Gail Whiteman, Chris Hope and Peter Wadhams.

nlike the loss of sea ice, the vulner- reach US$100 billion within ten years3. pivotal to the functioning of Earth systems ability of polar bears and the rising The costliness of environmental damage such as oceans and the climate. The release human population, the economic from development is recognized by some, of methane from thawing permafrost Uimpacts of a warming Arctic are being such as Lloyd’s3 and the French oil giant beneath the East Siberian Sea, off northern ignored. Total, and the dangers of Arctic oil spills are Russia, alone comes with an average global Most economic discussion so far assumes the subject of a current panel investigation price tag of $60 trillion in the absence of that opening up the region will be beneficial. by the US National Research Council. What mitigating action — a figure comparable to The Arctic is thought to be home to 30% of is missing from the equation is a worldwide the size of the world economy in 2012 (about the world’s undiscovered gas and 13% of its perspective on Arctic change. Economic $70 trillion). The total cost of Arctic change undiscovered oil, and new polar shipping modelling of the resulting impacts on the will be much higher. routes would increase regional trade1,2. The world’s climate, in particular, has been scant. Much of the cost will be borne by devel- insurance market Lloyd’s of London esti- We calculate that the costs of a melting oping countries, which will face extreme mates that investment in the Arctic could Arctic will be huge, because the region is weather, poorer health and lower

Bubbles of methane emerge from sediments below a frozen Alaskan lake.

agricultural production as Arctic warming varies with each tonne of carbon dioxide 15–35 years the average date at which the affects climate. All nations will be affected, not emitted or saved. global mean temperature rise exceeds 2°C just those in the far north, and all should be We ran the PAGE09 model 10,000 times to above pre-industrial levels — to 2035 for the concerned about changes occurring in this calculate confidence intervals and to assess business-as-usual scenario and to 2040 for region. More modelling is needed to under- the range of risks arising from climate change the low-emissions case (see ‘Arctic methane’). stand which regions and parts of the world until the year 2200, taking into account sea- This will lead to an extra $60 trillion (net pre- economy will be most vulnerable. level changes, economic and non-economic sent value) of mean climate-change impacts sectors and discontinuities such as the melt- for the scenario with no mitigation, or 15% ECONOMIC TIME BOMB ing of the Greenland and West Antarctic of the mean total predicted cost of climate- As the amount of Arctic sea ice declines ice sheets (see Supplementary Information; change impacts (about $400 trillion). In the at an unprecedented rate4,5, the thawing of go.nature.com/rueid5). We superposed low-emissions case, the mean net present offshore permafrost releases methane. A a decade-long pulse of 50 Gt of methane, value of global climate-change impacts is 50-gigatonne (Gt) reservoir of methane, released into the atmosphere between $82 trillion without the methane release; stored in the form of hydrates, exists on the 2015 and 2025, on two standard emissions with the pulse, an extra $37 trillion, or 45% East Siberian Arctic Shelf. It is likely to be scenarios. First was ‘business as usual’: is added (see Supplementary Information). emitted as the seabed warms, either steadily increasing emissions These costs remain the same irrespective of 6 over 50 years or suddenly . Higher meth- “There is a of CO2 and other whether the methane emission is delayed ane concentrations in the atmosphere will steep global greenhouse gases by up to 20 years, kicking in at 2035 rather accelerate global warming and hasten local with no mitigation than 2015, or stretched out over two or three changes in the Arctic, speeding up sea-ice price tag action (the scenario decades, rather than one. A pulse of 25 Gt of retreat, reducing the reflection of solar attached used by the Inter- methane has half the impact of a 50 Gt pulse. energy and accelerating the melting of the to physical governmental Panel The economic consequences will be Greenland ice sheet. The ramifications will changes in the on Climate Change distributed around the globe, but the model be felt far from the poles. Arctic.” Special Report on ling shows that about 80% of them will occur To quantify the effects of Arctic meth- Emissions Scenarios in the poorer economies of Africa, Asia and ane release on the global economy, we used A1B). Second was a ‘low-emissions’ case, in South America. The extra methane magni- PAGE09. This integrated assessment model which there is a 50% chance of keeping the fies flooding of low-lying areas, extreme heat calculates the impacts of climate change and rise in global mean temperatures below 2°C stress, droughts and storms. the costs of mitigation and adaptation meas- (the 2016r5low scenario from the UK Met ures. An earlier version of the PAGE model Office). We also explored the impacts of later, GLOBAL PROBLEM was used in the UK government’s 2006 Stern longer-lasting or smaller pulses of methane. The full impacts of a warming Arctic, includ- Review on the Economics of Climate Change In all of these cases there is a steep global ing, for example, ocean acidification and to evaluate the effect of extra greenhouse-gas price tag attached to physical changes in altered ocean and atmospheric circulation, emissions on sea level, temperature, flood the Arctic, notwithstanding the short-term will be much greater than our cost estimate risks, health and extreme weather while taking economic gains for Arctic nations and some for methane release alone. account of uncertainty7. The model assesses industries. To find out the actual cost, better models how the net present value of climate effects The methane pulse will bring forward by are needed to incorporate feedbacks that

this year’s protracted cold spell in Europe. ARCTIC METHANE Such integrated analyses of Arctic change Global mean temperatures will rise more must enter global economic discussions. But quickly if 50 gigatonnes of methane is released from permafrost beneath the East Siberian Sea. neither the World Economic Forum (WEF) in its Global Risk Report nor the Interna- With methane Without methane 6 tional Monetary Fund in its World Economic 9 No mitigation (business as usual) Outlook recognizes the potential economic 5 threat from changes in the Arctic. 4 2°C limit In 2012, noting that the far north is exceeded increasing in strategic importance and 3 in 2035 citing the need for informal dialogue C)

° 2 among world leaders, the WEF launched its Global Agenda Council on the Arctic. This 1 is welcome but more action is needed. The 0 WEF should kick-start investment in rigor- 2020 2040 2060 2080 2100 ous economic modelling. It must ask world 6 leaders to consider the economic time bomb Low emissions beyond short-term gains from shipping and 5 extraction. 4 2°C limit The WEF should also encourage innova- exceeded

Global mean temperature rise ( tive adaptation and mitigation plans. It will 3 in 2040 be difficult — perhaps impossible — to avoid 2 large methane releases in the East Siberian Sea without major reductions in global 1 emissions of CO2. Given that the methane 0 originates in local seabed warming, then 2020 2040 2060 2080 2100 reducing black carbon deposits on snow and ice might buy some precious time10. But The economic impacts of the methane pulse unknown factors could also mean that our will be felt worldwide. impact estimates are conservative. Methane No mitigation Low emissions 5 emerging in a sudden burst could linger for longer in the atmosphere, and trigger more 4 rapid temperature changes than if the gas were released gradually. 3 Arctic science is a strategic asset for Mitigation halves 2 extra costs human economies, because the region drives critical effects in our biophysical, political 1 and economic systems. Without this recog- US$ per year (trillions) nition, world leaders and economists will 0 2020 2040 2060 2080 2100 miss the big picture. ■ Solid lines indicate mean results from the PAGE09 model; dashed lines indicate con dence intervals, 5% (lower) and 95% (upper). Gail Whiteman is professor of sustainability, management and climate change at Erasmus University Rotterdam, are not included in PAGE09, such as linking the Netherlands. Chris Hope is a reader in the extent of Arctic ice to increases in Arctic policy modelling at Judge Business School, mean temperature, global sea-level rise and University of Cambridge, UK. ocean acidification, as well as including esti- Peter Wadhams is professor of ocean mates of the economic costs and benefits of physics at the University of Cambridge, UK. shipping. Oil-and-gas development in the e-mail: [email protected] Arctic should also, for example, take into 1. Gautier, D. L. et al. Science 324, 1175–1179 account the impacts of black carbon, which (2009). absorbs solar radiation and speeds up ice 2. Smith, L. C. & Stephenson, S. R. Proc. Natl Acad. melt, from shipping and gas flaring. Sci. USA 110, E1191–E1195 (2013). 3. Emmerson, C. & Lahn, G. Arctic Opening: Splitting global economic impact figures Opportunity and Risk in the High North (Chatham into countries and industry sectors would House–Lloyd’s, 2012); available at http:// raise awareness of specific risks, including go.nature.com/ruby4b. 4. Wadhams, P. AMBIO 41, 23–33 (2012). the flooding of small-island states or coastal 5. Maslowski, W., Kinney, J. C., Higgins, M. & cities such as New York by rising seas. Mid- Roberts, A. Annu. Rev. Earth Planet. Sci. 40, latitude economies such as those in Europe 625–654 (2012). 6. Shakhova, N. E, Alekseev, V. A, & Semiletov, I. P. and the United States could be threatened, for Doklady Earth Sci. 430, 190–193 (2010). example, by a suggested link between sea-ice 7. Hope, C. Clim. Change 117, 531–543 (2013). retreat and the strength and position of the jet 8. Francis, J. A. & Vavrus, S. J. Geophys. Res. Lett. 39, 8 L06801 (2012). stream , bringing extreme winter and spring 9. International Monetary Fund. World Economic weather. Unusual positioning of the jet stream Outlook (IMF, 2013). over the Atlantic is thought to have caused 10. Shindell, D. et al. Science 335, 183–189 (2012).