Chapter 5: The impacts of global warming – Flashcards
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What is the evidence of climate change in the Arctic?
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In the past few decades, average Arctic temperatures have risen at twice the rate of the rest of the world. Over the next 100 years, they could rise a further 3-5 degrees over land and up to 7 degrees over the oceans
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What has the impact of climate change been in the Arctic with regards to ice?
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Temperature rises are leading to the melting of the Greenland ice sheet, glaciers and sea ice
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How may ice melting in the Arctic further climate change?
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- Ice and snow reflect a lot of solar energy, so when they melt more energy is absorbed and warming increases - The melting of the ice could make the Arctic Ocean less saline and warmer. This could weaken the formation of the Arctic conveyor which draws the warm Gulf stream current northwards. The loss of the warm Gulf stream would cause dramatic cooling of the climate in northern western Europe - Water from melting ice sheets and glaciers will contribute to rising sea levels globally
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List the major impacts on natural systems that climate change has had in the Arctic
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- Vegetation shifts - Thawing of permafrost - Fires and insects - Ultraviolet impacts - Carbon cycle changes - Marine/Land species
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How has vegetation shifted as a result of climate change in the Arctic?
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Vegetation zones are predicted to shift northwards, with coniferous forests encroaching on taundra and ice deserts. This shift will destabilise existing food webs. The longer warmer growing season will be a benefit to Arctic agriculture although soils will be a limiting factor
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How has thawing of permafrost occurred the Arctic as a result of climate change?
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Up to 40% of total permafrost is expected to thaw, especially in Siberia. This will release huge quantities of methane- a greenhouse gas. In some areas, Due to changing positions of ice and wetlands, there will be an impact on species, particularly freshwater fish such as the Arctic char and lake trout
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How has climate change caused increasing fires and insects in the Arctic?
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Global warming will increase forest fires and insect caused-tree death, which may have an impact on old-growth forest, a valuable habitat that is rich in lichens, mosses, fungi and birds such as woodpeckers
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What ultraviolet impacts have there been in the Arctic due to climate change?
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Increased UV radiation will reach the Earth's surface as snow and ice cover is lost. Many freshwater ecosystems are highly sensitive to UV radiation, which destroys phytoplankton at the base of the marine food chain
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How has the impact of carbon cycle changes come as a result of climate change in the Arctic?
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The replacement of Arctic vegetation with more forests will lead to higher primary productivity and increased carbon dioxide uptake, but methane emissions from warming wetlands and thawing permafrost could counterbalance this positive effect
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What have been the impacts on animal species in the Arctic due to climate change?
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- Northward species shift - Impacts on marine and land species
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What effects on marine and land species have resulted from climate change in the Arctic?
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Marine species dependent on sea ice, including polar bears, walruses and some birds, will decline, some may face extinction and birds like geese will have different migration patterns Land species adapted to the Arctic climate, including the lemming, vole, Arctic fox and snowy owl are at risk
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How have there been Northward species shift in the Arctic as a result of climate change?
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Species will shift north with forests. Some species are likely to suffer major decline
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What have been the social impacts in the Arctic due to the ecological and environmental changes brought about by climate change?
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- Loss of hunting culture and decline of food for indigenous people - Decline in northern freshwater fisheries - Large areas of snow and ice melt, exposing new land and open sea, the Arctic therefore becomes vulnerable to exploitation of oil, gas, fish and other resources - Disruption of land based transport because of permafrost thawing - Need for herd animals to change their migration routes
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Why is the situation of climate change unethical in Africa?
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It's the continent that makes the least contribution to global warming, yet it is the most vulnerable to climate change
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Why is Africa so vulnerable to climate change impacts?
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Much of its population is dependent on climate-sensitive resources such as local water and ecosystems, and has a limited availability to respond to climate change because of poverty Two thirds of least developed countries are in Africa. The problem is made worse by conflicts like the Darfur in Sudan. An unjust trading system forces many countries to sell their exports at a low price to compete with subsidised European products. Above all, the burden of unpayable debt means no money is available for the mitigation of climate change and the introduction of adaptive strategies
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What are the seven major impacts of climate change in Africa?
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- Water issues - Food insecurity - Natural resources - Health - Development of coastal zones - Desertification
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How have water issues been created in Africa as a result of climate change?
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Life in Africa is regulated by access to water for agriculture, domestic use and hydroelectric power. Many large rivers like the Nile are internationally shared creating potential for conflict between users
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How has food insecurity been created in Africa as a result of climate change?
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Seventy percent of the population are subsistence farmers, many of whom will not be able to feed themselves should water supplies dry up, pasture quality deteriorate or crops fail
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Why have natural food resources become a problem in Africa due to climate change?
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Poor people, especially those living in marginal environments, depend directly on wild plants and animals to support their way of life. Loss of biodiversity due to climate change will threaten them
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How has health become a huge problem in Africa due to climate change?
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Vector borne diseases (malaria) and water borne diseases (diarrhoea) could increase with climate change. Moreover, 80% of health services rely on wild plants for remedies, which are under threat
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Why has the development of coastal zones been a problem in Africa from climate change?
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Movement of environmental refugees from the countryside puts pressure on coastal zones, especially in the north and west of Africa (shanty towns in Lagos and Freetown) Sixty percent of Africans live in coastal zones, many of which are at risk of coastal erosion and flooding. There's higher threat from these due to rising sea level. If these areas were flooded, much of the continent's infrastructure of roads, bridges and buildings would be lost
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Why is desertification a climate change related problem in Africa?
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Desertification is a major destroyer of grasslands. It is increased by unreliable or descreasing rainfall
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Why is predicting eustatic sea-level rise so complex?
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- The difficulty of estimating future greenhouse gas emissions - The difficulty of predicting the impact of thermal expansion of oceans and melting of ice sheets and glaciers - whether we adopt a 'business as usual' or sustainable scenario
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What's the meaning of eustatic change?
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Change in sea level due to change in the amount of water in the oceans
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What's the meaning of isostatic change?
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Movement of land in response to loss or gain of mass
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What are the three types of area vulnerable to sea-level rise?
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- The world's large river deltas (Nile, Mississippi) - Areas that lie close to sea level and are already defended (Netherlands) - Small, low lying islands (In Pacific and Indian Oceans)
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What have past emission levels been and what are they projected to rise to in 2035?
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Before the industrial revolution, CHG levels stood at 280ppm. In 2007, they stood at 430ppm and by 2035, with no attempt of reduction they could reach 550ppm (A 'business as usual' scenario)
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Give 3 major points about predicted growth of greenhouse gas emissions
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- Most future emissions growth will come from developing countries. India and China will contribute 75% of the increase - The link between economic development and growth of CHG emissions could be broken by use of green technologies - Despite increasing scarcity, supplies of fossil fuels exist to fuel emissions growth to well beyond 800ppm, including oil sands, oil shales and coal
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Predictions of emission levels and their impacts are difficult due to the difficulty of predicting what?
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- The level and nature of economic development, especially in countries like India and China - What degree of international action will be taken to reduce emissions - The impact of positive feedback - The inertia in the system - climate change will continue
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What's the meaning of the tipping point?
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The tipping point is reached when climate change occurs irreversibly and at an increasing rate
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What was the original agreement of the definition of the tipping point?
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At a level of 450oom carbon dioxide, and a threshold temperature of 2 degrees Celsius
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Give some examples of the visible manifestations of the tipping point
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The loss of the massive Greenland ice sheet, the melting of the West Antarctic ice sheet, the destruction of the Amazon forest and the collapse of the global ocean current system (known as the thermohaline circulation) all of which would lead to catastrophic changes
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What has essentially become the new evidence of the tipping point?
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Increasingly, geographers are talking about visible manifestations of the tipping point such as the loss of the Massive Greenland ice sheet, the destruction of the Amazon forest, the collapse of the global ocean current system etc/
