THE FORECAST IMPACTS OF GLOBAL WARMING. What could we be facing in the years ahead? How will the Arctic and Africa be affected?. Direct impacts – environmental, social and economic effects that occur in a specific place due to temperature and rainfall changes eg Arctic and Africa
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THE FORECAST IMPACTS OF GLOBAL WARMING What could we be facing in the years ahead? How will the Arctic and Africa be affected?
Direct impacts – environmental, social and economic effects that occur in a specific place due to temperature and rainfall changes eg Arctic and Africa • Indirect impacts – change that comes about as a result of the temperature and rainfall differences and this then causes impacts eg sea level change
Food forecast impacts • +0.5 – 6.1°C - Falling crop yields in many developing regions • +1.5 – 3.8°C - Rising number of people at risk from hunger (25 – 60% increase in the 2080s in one study with weak carbon fertilisation), with half of the increase in Africa and West Asia • +3.6 – 6°C - Yields in many developed regions decline even if strong carbon fertilisation • +4.1 – 5.8°C - Entire regions experience major declines in crop yields (e.g. up to one third in Africa)
Water forecast impacts • +0.6 – 2.1°C - Small mountain glaciers disappear worldwide - potential threat to water supplies in several areas • +2 – 4.3°C - Significant changes in water availability (one study projects more than a billion people suffer water shortages in the 2080s, many in Africa, while a similar number gain water • +2.1 – 3.8°C - Greater than 30% decrease in runoff in Mediterranean and Southern Africa • +4.2 – 5.9°C - Sea level rise threatens major world cities, including London, Shanghai, New York, Tokyo and Hong Kong
Ecosystems forecast impacts • +0.4 – 2 °C - Coral reef ecosystems extensively and eventually irreversibly damaged • +1.4 – 5.8 °C - Large fraction of ecosystems unable to maintain current form • +2 – 3.3 °C - Possible onset of collapse of part or all of Amazonian rainforest • +2.3 – 3.9°C - Many species face extinction (20 – 50% in one study)
Extreme weather forecast impacts • +1 – 5.4°C - Rising intensity of storms, forest fires, droughts, flooding and heat waves • +2.2 – 3.9°C - Small increases in hurricane intensity lead to a doubling of damage costs in the US
Risk of major irreversible change forecast impacts • +1.5 – 3°C - Onset of irreversible melting of the Greenland ice sheet • +1.5 – 6°C - Risk of weakening of natural carbon absorption and possible increasing natural methane releases and weakening of the Atlantic THC (Thermo Haline Circulation – the global ocean currents) • +3 – 6°C - Increasing risk of abrupt, large-scale shifts in the climate system (e.g. collapse of the Atlantic THC and the West Antarctic Ice Sheet)
Melting glaciers, ice-sheets and the Global Ocean Currents forecast impacts • For < 1°C - It has been "recently suggested that the threshold for an irreversible loss of the Greenland ice sheet may be as low as 1°C". • For 1–2°C - Climate models indicate the THC begins to show signs of moderate weakening • For 2–3°C - The THC weakens further, and collapse of the Greenland or West Antarctic ice sheets become even more likely • For 3–4°C - Coral reefs suffer catastrophic failure and the terrestrial biosphere becomes a net CO2 source • By 4–5°C - The THC may be pushed to the point of collapse
Impact on the world’s oceans • P 36-37 Oxford
THE Arctic….(compulsory case study) • P 52-54 Philip Allan • P 46-47 Pearson and on CD ROM • P 38-40 Oxford Essay: The impact of global warming on the Arctic Include: Impacts on the environment Socio-economic impacts Are there any benefits from global warming?
Why the Arctic? • It is generally agreed that the Arctic will react more strongly to global warming than any other region, so in that sense it is both a barometer of the impacts, and an early warning. Most models estimate warming will be double the global average in the Arctic. • In addition, there are indigenous people, which there are not in the Antarctic. • The region is a zone of increasing resource exploitation, and potential conflict, as fossil fuels are minerals that run out. • There is no ‘Arctic Treaty’ so the region is potentially vulnerable to disagreement.
Race to claim the Arctic 22 December 2007 From New Scientist Print Edition. Rowan Hooper • "This isn't the 15th century," exclaimed an indignant Canadian foreign minister. "You can't go around the world and just plant flags and say: 'We're claiming this territory'." Except that's exactly what Russia did in August when it audaciously plonked a flag on the seabed under the North Pole, and lodged a claim of sovereignty with the United Nations. • Protestations apart, Canada has hardly been idle itself in the Arctic. In its own show of strength, in July it announced it would spend a hefty US$7 billion patrolling the Arctic Circle with icebreakers, and after Russia planted its flag, Canada announced plans for a military training base on Nunavut in its far north. • The dash to claim the "Arctic El Dorado" is well and truly on, and the reasons why the race started in earnest in 2007 are twofold. First, the summer sea ice melted more than ever. This means the prospect of plundering the Arctic seabed for its riches of oil, gas and minerals is closer than ever. Similarly, the fabled North-West Passage became navigable for the first time, which could slash thousands of miles off the shipping route from Europe to Asia. • The second reason is that claims to the Arctic shelf made under the UN Convention on the Law of the Sea must be made within a decade of ratifying it, so Russia only has until 2009, Canada until 2013, and Denmark until 2014. • As the ice melts, the Arctic squabbling continues. Denmark says it has a claim to the North Pole, via its self-governing province of Greenland. The Canadians say the pole is theirs, while Russia has already set down its flag. Funny how there's less clamour to preserve the ice than there is to plunder the riches beneath it.
There are growing concerns about the future of the Arctic, these can be summarised as: • Fears over the future of the Greenland Ice Cap. Recent research suggests melting is increasing, and the rate of melting is beyond the range of most predictions. • Fears over the loss of ecosystems associated with the tundra. Whilst biodiversity is low, within certain species groups it is very high; Arctic flora and fauna cannot migrate north, unlike lower latitude ecosystems. • Fears that this vulnerable area will be the next great resource frontier (see previous article) adding to pressures from climate change. • Concerns that culture and tradition among the indigenous people will be swept aside as climate change accelerates.
In terms of indigenous people, the Arctic has a population of about 4 million, but there are numerous indigenous groups and sub-groups:
Despite much modernisation, many indigenous people are still heavily dependent, directly, on the natural environment for some or all of their resources. In this sense they are especially vulnerable to change.
Arctic climate headlines: • 3-4C warming since the 1950s • 6-8C warming by 2100 considered a distinct possibility • Increased river discharge • 10% decline in snow cover since late 1970s • 10-20% decline in snow cover expected by 2070 • Precipitation increased 8% since 1900, mostly as rain; further increases expected • Permafrost has warmed by 2C since 1970s; shifts northward of the permafrost zone of 100s km are expected.
Summary of observed and potential ecological impacts: Outbreaks of insects Observed impacts - Spruce bark beetle is already on the rise; up to 2 million hectares of spruce forest already damaged Potential impacts - Likely to increase, as 2 year + hard frosts become rare and beetle larvae survive Forest fires Observed impacts - Areas burned have doubled in western North America since the 1970s Potential impacts - A further 80% increase in annual forest fires is expected by 2100 Agriculture Observed impacts - Little impact so far Potential impacts - Significant changes could increase growing seasons, allowing more land to be converted to grazing Polar Bears Observed impacts - Growing concern over falling numbers in some regions Potential impacts - An ice free Arctic could see populations crash, as bears rely on ice for transport; populations used to isolation are unlikely to survive increasing contact with Browns and Grizzlys
Ice dependent seals Observed impacts - These are seals which give birth on sea ice, and haul themselves onto sea ice e.g. ringed seals Potential impacts - Similar to polar bears, many species so depend on sea ice that their populations may become extinct. Cod and Shrimp Observed impacts - These fisheries have already been observed as closely related to climate Potential impacts - Cod populations could expand hugely as climate warms, whereas shrimp populations are likely to crash Tundra Plants Observed impacts - Vegetations zones are already changing, with and advance of forests and loss of grassland Potential impacts - If permafrost continues to melt, long term waterlogging will significantly change flora and insect life over large areas, with knock-on effects to large mammals. Ice crusting Observed impacts - This occurs when unexpected winter thaws are followed by fresh snowfall; this prevents Lemmings, Musk Ox and Caribou from digging through the snow to forage Potential impacts - Population collapses are highly likely due to winter starvation
Arctic Summary • The arctic ecosystem is highly vulnerable as it is deeply adapted to an intense, seasonal climate. It relies upon a continuous, very cold winter. • There is evidence that this winter is fast disappearing to be replaced by more variable cold-thaw conditions which lead to iceing, fails to kill pests, and promotes waterlogging. • Many species are not in a position to migrate to new latitudes, and others which depend directly on sea ice may simply disappear.
January 8, 2008 (New York Times) In Greenland, Ice and Instability By ANDREW C. REVKIN • The ancient frozen dome cloaking Greenland is so vast that pilots have crashed into what they thought was a cloud bank spanning the horizon. Flying over it, you can scarcely imagine that this ice could erode fast enough to dangerously raise sea levels any time soon. • Along the flanks in spring and summer, however, the picture is very different. For a lengthening string of warm years, a lacework of blue lakes and rivulets of meltwater have been spreading ever higher on the ice cap. The melting surface darkens, absorbing up to four times as much energy from the sun as unmelted snow, which reflects sunlight. Natural drainpipes called moulins carry water from the surface into the depths, in some places reaching bedrock. The process slightly, but measurably, lubricates and accelerates the grinding passage of ice toward the sea. • Most important, many glaciologists say, is the breakup of huge semis-ubmerged clots of ice where some large Greenland glaciers, particularly along the west coast, squeeze through fjords as they meet the warming ocean. As these passages have cleared, this has sharply accelerated the flow of many of these creeping, corrugated, frozen rivers. • All of these changes have many glaciologists “a little nervous these days — shell-shocked,” said Ted Scambos, the lead scientist at the National Snow and Ice Data Center in Boulder, Colo., and a veteran of both Greenland and Antarctic studies. • Some fear that the rise in seas in a warming world could be much greater than the upper estimate of about two feet in this century made by the Intergovernmental Panel on Climate Change last year. (Seas rose less than a foot in the 20th century.) The panel’s assessment did not include factors known to contribute to ice flows but not understood well enough to estimate with confidence. All the panel could say was, “Larger values cannot be excluded.” • A scientific scramble is under way to clarify whether the erosion of the world’s most vulnerable ice sheets, in Greenland and West Antarctica, can continue to accelerate. The effort involves field and satellite analyses and sifting for clues from past warm periods, including the last warm span between ice ages, which peaked about 125,000 years ago and had sea levels 12 to 16 feet higher than today’s. • The Arctic Council, representing countries with Arctic territory, has commissioned a report on Greenland’s environmental trends, to be completed before the 2009 climate-treaty talks in Copenhagen, at which the world’s nations have pledged to settle on a long-term plan for limiting human-caused global warming.
Key Arctic web resources: • The National Oceanographic and Atmospheric Administrations Arctic resource pages: http://www.arctic.noaa.gov/ • The IPCC 4th Assessment regional report chapter (15) on impacts in the Polar Regions: http://www.ipcc.ch/ipccreports/ar4-wg2.htm • The Arctic Climate Impact Assessment (ACIA) 2005 http://www.acia.uaf.edu/ • The Arctic Council website http://www.arctic-council.org/
Africa…(Compulsory case study) • P55-56 Philip Allan • P45-46 Pearson and on CD ROM • P 41-43 Oxford • Produce a power point presentation to answer the exam question: Why does climate change present potential problems for the African continent? Remember to include information about the environmental, social, economic and political effects
Africa • Africa makes the least contribution to global warming worldwide • However, it experiences a large number of the consequences • Predicted temperature change 4-5°C higher than the global rate • Rainfall is likely to increase in the equatorial region, but decrease to the north and south of that band.
Likely effects? Water Issues • Water regulated by access to hydro-electric power, domestic and industry • Many of the larger rivers (River Nile) are internationally shared – causing conflict • Could lead to wars, global migrations and famine • Food Insecurity • 70% of population are subsistence farmers, many of whom will not be able to feed themselves if the water supplies dry up • Increased locust plagues may also threaten food supplies
Natural Resources • Loss of biodiversity due to climate change will threaten poorer people who are dependent on wildlife Health • Vector borne and water borne diseases could increase with climate change • 80% of remedies rely on wild plants that are under threat. Development of Coastal Zones • 60% of Africans live in coastal zones • Make shanty towns in cities such as Accra, Freetown and Lagos • Coastal zones are at risk of coastal erosion and rising sea levels Desertification • Major destroyer of grassland • Increased by unreliable or decreasing rainfall