Spec S4

Question 1

What is the importance of the carbon cycle?

Answer 1

• All living organisms depend on carbon, which is a fundamental building block of life
• Green plants and phytoplankton extract carbon from the atmosphere in the process of photosynthesis, they are primary producers in ecosystems, converting sunlight and CO2 to carbohydrates, which support all consumer organisms, including humans
• Carbon stores such as ocean sediments and carbonate rocks lock away carbon for millions of years, helping to maintain atmospheric CO2 at levels conducive to life on the planet
• Decomposition and oxidation ensure that CO2 is recycled rapidly, replenishing stores of CO2 in the atmosphere for photosynthesis
• CO2 and CH4 in the atmosphere are important GHGs, absorbing long-wave radiation from the Earth’s surface and contributing to the natural greenhouse effect
• The carbon cycle operates in a state of dynamic equilibrium, with carbon moving continuously between stores, over millions of years a balance exists between flows of carbon into and out of stores, but on shorter timescales the amount of carbon held in the atmosphere can vary

Question 2

Examples of negative feedback

Answer 2

Expansion of forests
Increased Cloudiness
Increased aerosols in the atmosphere

Question 3

Expansion of forests

Answer 3

Temperatures rise, tree line advances polewards, expansion of forests absorbs more CO2 from the atmosphere

Question 4

Increased cloudiness

Answer 4

Higher temperatures, higher rates of evaporation and levels of atmospheric water vapour, increases cloud cover increases reflection of incoming solar radiation (albedo) back into space and lower temperatures

Question 5

Increased aerosols in the atmosphere

Answer 5

Burning fossil fuels releases tiny airborne particles (aerosols) of smoke, dust and sulphur to the atmosphere, they reflect incoming solar radiation back into space which lowers global temperatures - known as global dimming

Question 6

Examples of positive feedback

Answer 6

Increased evaporation
Reduced albedo
Declining forest cover
Increased cloudiness
Release of methane hydrates
Melting of permafrost
Increased ocean acidity

Question 7

Increased evaporation

Answer 7

Global warming intensifies evaporation from ocean and land surfaces, atmospheric water vapour increases, raises global temperatures, further evaporation

Question 8

Reduced albedo

Answer 8

Higher temperatures, melting of glaciers, sea ice and snow fields, reduces albedo, more solar radiation absorbed, temperatures increase, more melting

Question 9

Declining forest cover

Answer 9

Higher temperatures, tropical forest trees become stressed and die, releases CO2 from biosphere, higher temperatures, threatens more forests

Question 10

Increased cloudiness

Answer 10

Higher temperatures, increased evaporation, more water in atmosphere, increased cloud cover, help retain heat from Earth and contribute to further temp rise, more evaporation

Question 11

Release of methane hydrates

Answer 11

Methane hydrates are locked away in ocean sediments, stability of this carbon store depends on temperature, as oceans warm there is potential for massive release of methane, a GHG 20x more potent than CO2

Question 12

Melting of permafrost

Answer 12

CH4 and CO2 stored in vast quantities in permafrost, as temperatures rise this is melted and the GHGs are released, creating enhanced greenhouse effect, further warming and more melting

Question 13

Increased ocean acidity

Answer 13

As oceans absorb more CO2, become more acidic, this reduces oceans’ capacity to absorb CO2, in long term this increases CO2 in atmosphere, contributes to greenhouse effect

Question 14

Mean global temperature change

Answer 14

• All of IPCC projections for next 70-80 years show significant rises in mean global temperatures during the 21st century
• Depending on trajectory of GHG emissions, temperature increases range from 0.3 degrees to 4.8 degrees, however a mean global temperature rise of around 2 degrees is the most likely scenario

Question 15

Mean global sea level changes

Answer 15

• Rising sea level is the result of thermal expansion of the oceans due to warning and the loss of ice by ice sheets and glaciers on land
• Ice losses are caused by surface melting and increased rates of glacier flow
• Sea level has been rising since the onset of industrialisation in the mid 19th century
• 1901-1990 = mean global sea level rose by 1.5mm/yr
• 1990-2010 = mean global sea level rose by 3.0mmyr
• IPCC forecasts indicate an even more rapid rise during the rest of the 21st century
• Forecasts depend on the future trend of GHG emissions, current projections suggest a minimum rise of 0.3m by end of the century, and maximum of 1m
• Most pessimistic forecast doesn’t;t include potential collapse of marine-based sections of West Antarctic ice sheet, could substantially increase the 1m figure

Question 16

What impacts can climate change have on marine ecosystems?

Answer 16

• Global warming raises sea surface temperatures
  CORAL REEFS
• Coral reefs (one of most biodiverse and productive ecosystems on the planet) currently being threatened by bleaching, caused by higher SSTs
• Bleaching and death of corals are possible with only a small rise in water temperature (1-2 degrees), in the last 30 years Indonesia has lost half of its reefs to bleaching, in Caribbean the proportion has reached 80%
  ARCTIC
• Warming of Arctic Ocean, shrinking of sea ice, decimated ice algae, which are the base of the marine food chain
• Sea ice also cortical to the survival of marine mammals such as walrus and seals
• Walrus use the coastal sea ice as diving platforms for foraging on sea bed and travel long distances on floating ice, seals use sea ice to rest, give birth and raise pups
• Exposed on ice, they are hunted by polar bears, the disappearance of sea ice is the main reason for a projected two thirds decline in the polar bear population by mid-century
• Few human groups rely directly on natural ecosystems, exception is the indigenous Inuit hunters of the Arctic, whose economy and culture depend on hunting marine mammals, especially seals, walrus and whales
• Thinning and melting of the sea ice makes hunting hazardous, with more open water in the Arctic, the number of killer whales is increasing, as natural predators of narwhals and seals, killer whales are in direct competition with Inuit hunters
  FOOD SUPPLY / FISHING
• Around UK, average SSTs have risen by 1.6 degrees since 1980, warming seas limit food supplies, growth rates and spawning for many fish species
• Therefore, some indigenous cold water species (eg. cod, haddock) had moved northwards towards Iceland whilst warm water species such as sea bass have migrated into UK waters
• This movement impacts the UK fishing industry, not only will commercial fishing have to switch to new species but the fishing effort for cold-water fish like cod will have to shift northwards

Question 17

What impacts can climate change have on terrestrial ecosystems?

Answer 17

• Temperatures are rising faster in the tundra than in any other ecosystem
  HABITAT CHANGE
• As permafrost thaws, wetland areas expand, attracts more migratory birds, influxes of spring migrants from the south will occur sooner, breeding season will last longer and higher temperatures will ensure an abundance of insects
• Southern fringes of the tundra will lose their open aspect as the tree line advances north, as forests replace the tundra, changes in habitat will affect indigenous plant and animal species
• Migration patterns across caribou (which spent summer on the tundra) will be disrupted, as open tundra habitats shrink, predators such as snowy owls and arctic foxes which rely on the lemming population will be forced upwards
• Cairngorms in north east Scotland supports the most extensive mountain tundra in the British Isles, several animal species such as arctic hares are restricted to this type of habitat, it is estimated that a 1 degree rise in temperature requires an uphill movement of 200-275m to maintain the same habitat, animals living at 600m would have to move to 800m - even with this small warming, Scotland would lose 90% of its arctic-alpine habitats, if warming continues these species would eventually run out of suitable habitat and face extinction
  PHENOLOGY
• Phenology is the study of changes in the timing of sprint and other natural seasonal events, it is in indicator of global warming
• According to the IPCC, in the past 30 years sprint has occurred earlier by 2.3-5.2 days per decade on average, this creates a loss of synchronisation between species, animals awaken from hibernation or start to breed before the emergence of food resources such as leaves or insects

Question 18

What impacts can climate change have on human health?

Answer 18

• World Health Organisation forecasts an additional 250,000 deaths per year worldwide between 2030 and 2050 linked to climate change and the spread of infectious disease, malnutrition and diarrhoea
  VECTOR-BORNE DISEASE
• Climatic change stimulates transmission of vector-borne diseases and their geographic range, dengue fever, a disease spread by the Aedes mosquito and formerly confined to the tropics and sub-tropics, is today found in 28 US states
• Between 1995-2005, 4000 cases were reported, rising temperatures and increased rainfall have favoured the spread of mosquitos carrying the disease
• Climate change also responsible for spread of Lyme disease in the USA, the disease is transmitted by ticks, which thrive in warmer conditions - currently distribution is expanding northwards, it is likely that the disease carrying ticks will eventually colonise Canada
• Malaria leading cause of death in developing world, claims around 800,000 lives per year, the mosquitos that spread it thrive in warm, wet conditions, disease is seasonal throughout tropical Africa, in a warmer and wetter world, the disease could spread to malaria-free parts of the world including southern Europe and Mediterranean
  FOOD POISONING
• Higher temperatures increase risk of food contamination by salmonella and other bacteria which cause food poisoning
• Heavier rainfall increases flood frequencies and the probability for water supplies being polluted by human waste, bacteria in drinking water will multiply the risk of diarrhoea (already a major cause of death among children in LIDCs)
  FOOD SECURITY
• Health could be compromised by droughts and floods reducing crop yields and food production, which could threaten food security and human health with widespread malnutrition and under nutrition in LIDCs
• Global food supply has already been reduced by climate change and forecasts by the IPCC suggest significant reduction in staple cereal crops by 2030

Question 19

What impacts can climate change have on weather?

Answer 19

EVIDENCE OF EXTREME WEATHER
- Rising temperatures are known to disrupt the middle latitude and sub-tropical jet streams, increase evaporation and humidity and modify pressure patterns both in the atmosphere and at the surface
- Since mid-1970s, the frequency, intensity and duration of extreme weather have increased, eg. the 2005 hurricane season in the North Atlantic Caribbean area produced a record-breaking number of storms, including five category 5 hurricanes and in August 2015, for the first time, three large hurricanes were active simultaneously in the Pacific
- Sahel region of Africa has endured numerous severe droids in the past 40 years, which have accelerated desertification, in 2015, California entered its fourth successive year of drought
IMPLICATIONS
- Heavier and more frequent rainfall events associated with depressions and thunderstorms will cause severe river floods, groundwater floods such as those that devastated the Somerset Levels in winter 2014 will become more common, possible responses: engineering to strengthen hard flood defences, managed land-use change in catchments to delay run-off and restrictions on housing and infrastructure on active floodplains
- More powerful tropical cyclone which generate huge storm surges threaten populations in low-lying coastal areas, Hurricane Katrina caused massive loss of life and economic damage in New Orleans and along the Gulf coast in August 2005
- More frequent and more powerful depressions will accelerate rates of coastal erosion in mid-latitudes, nations will have to choose between hard defences to give complete protection, coastal realignment which allows the coastline to retreat inland and form natural defences such as mudflats and salt marshes or non-intervention allowing erosion and disposition to establish a new equilibrium
- Heatwaves expected to occur with greater frequency in the future, posing a direct threat to human health especially to vulnerable groups like the elderly in urban areas where the heat island effect is most intense - an exceptional and prolonged heatwave struck much of Europe in summer 2003, beginning in June and continued until mid-August, causing an estimated 30,000 excess deaths, most of the victims were aged 75 or above, mitigating the health impact of heatwaves in future will include early warnings, informing vulnerable groups of the precautions they should take and greening urban areas to promote evaporation and cooling

Question 20

What does the vulnerability of people to climate change depend on?

Answer 20

Where they live
Ability to cope

Question 21

How does where people live impact their vulnerability to climate change?

Answer 21

FARMING
- Most rural communities in the developing world are subsistence farmers, the majority depend on direct rainfall for successful cultivation of crops and raising of livestock, however climate change will make rainfall more erratic and floods and droughts will become more frequent
- These problems will hit farmers hardest in marginal farming environments where rainfall is only sufficient enough to support agriculture
- Since 1970s, extensive areas of crop and grazing land in the Sahel in northern Africa have been abandoned due to severe land degradation and desertification, prolonged droughts linked to climate change have been extremely harmful
- Other farming regions likely to be affected by drier conditions in the future include prime agricultural areas such as Prairies in North America
GLACIERS
- 98% of world’s glaciers currently retreating, means that regions that rely on glacial meltwater for irrigation will almost certainly experience water shortages in future, some of the rural regions affected such as northern India and eastern China are among the most densely populated places in the world
FLOODING
- Populations in low-lying coastal regions in the tropics and sub-tropics are vulnerable to flooding caused by a combination of rising sea level and more powerful tropical storms
- Once again people in poorer countries are at most risk, storm surge in Bangladesh in 1991 killed 138,000 people, vs Hurricane Katrina (one of most powerful storms on record) in 2005 which killed just over 1400
- Storm surges not only cause loss of life but destroy crops and livestock, and leave over-stalinised soils and contaminated water supplies
ARCTIC
- Global warming is most rapid in the Arctic, where the thawing of permafrost and melting of sea ice threaten the livelihoods of native Inuit hunters

Question 22

How does people’s capacity to cope impact their vulnerability to climate change?

Answer 22

• Inequality and poverty at a global scale mean those at greatest risk are concentrated in the world’s poorest countries, people living in poverty have fewest entitlements to protect themselves and their families against natural climatic hazards and to cope with losses of crops, property and steep rises in food prices
• The elderly, young and chronically ill are among those least able to cope with the effects of climate change, this is illustrated by the impact of heatwaves in densely populated urban areas
• Prolonged spells of extreme temperature like the heatwave that struck Europe in summer 2003 caused 35,000 deaths and the majority of them elderly people age 75 and over

Question 23

Vulnerability of the environment to climate change

Answer 23

TUNDRA
- Rising temperatures melt permafrost, disrupts vegetation, creates extensive thaw lakes and wetlands, initiating mass movement
- Forests will invade the southern margins of the tundra
MOUNTAINS
- Glaciers will retreat in warmer conditions, thawing and glacier retreat will make slopes less stable and trigger more frequent mass movements
- The snow line will recede upslope and the winter snowpack will thin, these changes will reduce meltwater inputs to rivers
RAINFOREST
- Computer models predict that Amazon rainforest will become warmer and drier by mid 21st century
- As deforestation increases (partly due to climate change) the water cycle will weaken, creating positive feedback and accelerating forest loss - 30-60% of the Amazon rainforest rainforest could become dry savanna grassland by the end of the century
COASTS
- Higher sea levels and more powerful storms will increase rates of erosion on both upland and lowland coasts
- Shorelines will retreat inland, coastal environments at particular risk include dunes, salt marshes and mudflats

Question 24

What are the key mitigation strategies used to cut global emissions of GHGs?

Answer 24

Energy efficiency and conservation
Fuel shifts and low carbon energy sources
Carbon capture and storage
Reforestation and forest conservation

Question 25

Energy efficiency and conservation

Answer 25

• In the UK, domestic demand accounts for nearly 1/3 of primary energy consumption, service activities based in offices account for another 16%
• Already in the UK, building regulations ensure that new homes and offices conform to minimum standards of heat insulation and limits to the ratio of window/door space to floor area
• Energy performance certificates are required for all new buildings completed since 2008
• Government, local authorities and energy companies provide financial incentives to eligible householders to insulate lofts and cavity walls

Question 26

Fuel shifts and low-carbon energy sources

Answer 26

• Has been a steady decline in overall energy consumption since 2005, energy use fell by 6.6% in 2014 despite economic growth of nearly 3%
• There was a marked reduction in the use of coal and oil between 1990 and 2014, by 2014 coal consumption had fallen to levels not seen since the nineteenth century
• The contribution of renewables has expanded, albeit from a very low base
• These fuel shifts can be explained by advances in energy conservation and energy efficiency, and government policies to decarbonise the UK economy
• UK has to conform to EU’s Renewable Energy Directive, under this the UK has to achieve a 15% target for electricity generation from renewables by 2020, its strategy includes expanding renewables (esp wind power in offshore locations), closing several large, coal-fired power stations (eg. Ferrybridge 2015) and converted some coal-fired stations to biofuels
• This conversion is already taking place at Drax in North Yorkshire, by 2018 3/6 units will burn biomass fuel instead of coal
• Nuclear generated electricity has been an important part of the UK’s energy mix since the 1960s, however the contribution of nuclear power has fallen in the past decade as a number of older stations have been decommissioned
• Despite significant progress in the past 10 years, the UK still relies on fossil fuels for 86% of its energy supply, remaining a long way from a decarbonised economy and lagging well behind nations such as Denmark, Sweden and Germany

Question 27

Carbon capture and storage

Answer 27

• CCS is a new technology that extracts CO2 emitted by coal-burning power stations and transfers it to long-term storage underground
• It has the potential to drastically cut anthropogenic emissions of CO2, however even when the technology has been perfectly use of CCS may be limited by costs and a shortage of suitable storage sites, such as old oil and gas fields

Question 28

Reforestation and forest conservation

Answer 28

• Deforestation, mainly in the humid tropics is responsible for around 1/5 of global carbon emissions
• Reforestation and forest conservation are the cheapest and most effective strategies to combat and slow climate change
• UN has taken a lead in promoting its Reducing Emissions from Deforestation and Forest Degradation (REDD) programme, scheme gives a financial value to the carbon stored in forests by providing incentives to developing countries to conserve forests and reduce GHG emissions

Question 29

Types of adaptation strategies

Answer 29

Retreat
Accommodation
Protection

Question 30

Retreat strategies

Answer 30

• In coastal zones, rising sea level adds to risk
• One response is managed realignment, where vulnerable coastlines with few settlements are set back inland, where the risks of flooding and erosion are less
• In England and Wales this policy, supported by the DoE, DEFRA and local authorities is applied in Shoreline Management Plans
• River valleys are also at increased risk of flooding due to climate change, retreat policies operate in this environment in the UK and many other ACs
• Land use zoning can prevent housing and businesses from locating on floodplains
• Retreat strategies may not be an option for coastal and valley communities in the world’s poorest countries
• Poverty dictates that nearly 140 million people live in the Ganges-Brahmaputra Delta, a region of high risk, exposed to storm surges and violent river floods, despite the storm surge disasters of 1970 and 1991, which caused huge loss of life, the population of the delta has continued to grow rapidly

Question 31

Accommodation strategies

Answer 31

FARMING
- Climate change will affect growing conditions, crop types, cultivation practices and crop yields, therefore agriculture will have to adjust
- New crop strains will be developed, adapted to sorter or longer growing seasons, irrigation will be extended in regions of water shortage and there will be more efficient irrigation systems such as lined irrigation canals and drip irrigation
- Other methods to conserve soil moisture include rotating crops, growing drought resistant crops and using smaller fields to reduce evapotranspiration
- Whilst farmers in rich countries can accommodate change, those in poor countries with limited access to credit and capital will struggle to adjust
WATER SUPPLY
- Action is already taken to make water usage more efficient by reducing losses to leakage, recycling waste water and using grey water (from showers, baths etc) for gardens and flushing toilets
- More expensive options include increasing reservoir capacity, the desalination of seawater and the construction of pipelines and canals for inter-basin transfers of water from areas os surplus to areas of deficits
- In the developing world, water consumption per capita is relatively small and capita is in short supply, even so water could be further conserved by more efficient irrigation systems, the construction of ponds and reservoirs and by reducing losses to run-off
IMPROVING EDUCATION
- Early warning of extreme weather events allows the public in developed countries to prepare for floods, storm surges, gales and blizzards, thanks to modern satellite communications, smart phones and the internet, this is also beginning to happen in the developing world

Question 32

Protection strategies

Answer 32

COASTS
- Hard engineering structures (eg. sea walls) are used to protect coastal communities from flooding and erosion, storm surge barriers such as those on the Thames protect low-lying coasts at risk of flooding from violent storms an rising sea level
- Hard defences such as storage reservoirs and levees protect communities at risk from river floods
- Whilst large-scale , capital-intensive flood defences are beyond the means of most countries in the developing world, sot engineering offers a cheaper and more sustainable option
- Conservation of beaches, salt marshes and mudflats provides natural barriers against flooding and erosion in coastal areas
RIVER AREAS
- In river catchments, natural water storage can be increased by expanding areas of wetland, and run-off can be controlled by afforestation and other land-use changes
- Halting deforestation in developing countries in the tropics and sub-tropics would help control river flood and provide much-needed protection for vulnerable communities
- In cities, urban heat islands can be moderated by increasing reflection from urban surfaces, planting trees, creating areas of open water and reducing energy consumption
HEALTH
- Climate change is a threat to human health directly through natural hazards and indirectly through infectious diseases and food shortages
- In warmer and wetter conditions, vector and water borne diseases will become more widespread
- Communities can be protected from vector-borne diseases like malaria through control of mosquitos with pesticides as well as drugs, new vaccines and the use of bed nets
- Improved water treatment and sanitation together with screening for pathogens could protect millions of people from the threat of water-borne disease such as typhoid and cholera

Question 33

Future adaptations to housing and commercial buildings

Answer 33

HIGH TEMPERATURES
- Heat adaptive strategies: air conditioning and fans, limit solar gain by reducing window areas and south-facing windows, insulation to reduce external heat gain, increase albedo with reflective roofing (eg. white roofs) and white walls, improved ventilation (eg. night-time cooling with open windows), install sun-shades over windows, high-efficiency lighting to avoid emitting waste heat, air-tight buildings to prevent heat entering from outside
FLOODS
- Relocating more important and valuable services from basements and ground floors, in office blocks use these spaces for parking
- Green roofs to increase interception, storage and evapotranspiration
- Houses built on stilts or in coastal regions, floating houses to counter sea level rise
DROUGHTS
- Rainwater harvesting (collecting run-off from roofs and gutters) and using in grey water systems eg. flushing toilets, watering gardens

Question 34

Future adaptations to cities

Answer 34

HIGH TEMPERATURES
- Altered heat exchanges create an urban heat island effect, this will be addressed by: creating green infrastructure and replacing concrete and tarmac with trees, shrubs and grass where possible, greening cities increases evapotranspiration and cooling, trees also provide shade
- Future policies will aim to protect existing green space and enhance it wherever possible
- Will also involve increased reliance on renewable energy rather than combustion, which adds to urban heat generation
FLOODS
- By favouring changes in land use that conserve natural ecosystem principles, evaporation can be increased and run-off reduced and slowed
- Increasing the green cover, with greater interception of rain, more evapotranspiration and soil storage
- Replacing impermeable rads and walkways (concrete, tarmac) with permeable paving
DROUGHTS
- Develop storage systems to capture run-off and recycle water for domestic, commercial and industrial users

Question 35

Future adaptations to transport

Answer 35

EXTREME WEATHER
- Winter of 2014 in UK showed how parts of the rail network are vulnerable to extreme weather, storm waves destroyed part fo the sea wall at Dawlish in Devon, severing thr only rail link between Cornwall and the rest of the country, repaired after 6 weeks
- This example showed that railways on the coast are vulnerable to rising sea level and powerful storms, future strengthening of sea walls and dykes will be needed and i some cases, rail routes diverted inland
- Also in winter 2014, the Somerset Levels experiences severe flooding, interrupting rail services to the West Country, low lying parts of the rail network in river valleys or close to sea level will require protection, either by building flood barriers or elevating sections of track
HIGH TEMPERATURES
- Warmer summers increase the problems of rails buckling in extreme heath, this problem can be overcome by improved sleepers and rail fastenings
- The road network is vulnerable to high summer temperatures which melt tarmac and cause rutting
LOW TEMPERATURES
- Although winters in UK are likely to become milder, extreme cold spells cause freeze0thaw action, leading to the formation of potholes and damage to road surfaces, changes in the grades of asphalt can help to counteract both emblems
- Meanwhile, heavier rainfall and higher river flows could damage bridges
- Faster currents scour the piers and abutments and can induce bridge collapse
- The solution is to improve maintenance and protect piers and abutments either with rip-rap or concreting around foundations
DROUGHTS
- More frequent and prolonged droughts will disrupt traffic on major European waterways such as the Rhine and the Danube
- In low flow conditions, when water depth falls below 1.6m, traffic comes to a standstill, fleet modification and river engineering are adaptations that can maintain traffic in times of low flow
- Fleet modification would involve the use of barges with reduced drought, buoyancy aids allowing vessels to sit higher in the water, and couple convoys
AIRLINES
- Strong headwinds reduce landing rates when aircraft on their final approach are separated by distance, at Heathrow airport, a new system based on time separation allows more aircraft to land within a given time frame during stiff headwinds, the system is likely to be widely adopted
- Among other problems facing air transport are airport flooding, heat damage to runway surfaces, sea level rise threatening airports on the coast, increases in the strength of the jet stream and more convective thunderstorm weather
- As convectively thunderstorms occur more often in future, flights will be delayed and flight paths changed, increasing costs and flight duration
- Higher temperatures also mean less dense air and aircraft needing longer runways for take off

Question 36

Future adaptations to economies

Answer 36

• Difficult to predict how a country’s economy will adapt to climate change, most ACs will probably accommodate the worst effects, others, mainly in the developing world, will be harder hit, in all countries adapting to climate change will be costly and spending in this area will limit investment elsewhere and weaken economic growth
• Most LIDCs are situation in the tropics and sub-tropics where a rise in global temperature of 2 degrees or more will have much greater significance than in cooler climates
• Many LIDCs depend heavily on climate-sensitive activities such as agriculture and tourism, unable to adapt to drought and shifting rainfall patters, tens of millions of African farmers will become climate refugees, most will migrate to towns and cities
• In Asia, declining flows of major rivers fed by glaciers could reduce crop yields at the same time as population and demand are growing, problems of food production will be compounded if rising sea level forces the abandonment of farming in densely populated rover deltas like the Ganges-Brahmaputra in India and Bangladesh
• The outcome for many economies will be rising prices, inflation, unemployment, food insecurity and declining exports