climate change Flashcards
Global effects of climate change-
- Man of theworld’s glaciers and ice caps are shrinking
- artic sea ice is less extensive than in the past affecting wildlife such as polar bears- however, this may provide oppurtunities for ships to use the North West Passage in the future
- Low- lying Pacific Islands such as Tuvalu and the Maldives are under threat from sea-level rise
- Sea levels may rise by 1m by 2100 flooding agricultural land in Bangladesh, Vietnam, India and China.
What is the recent evidence for climate change?
Shrinking glaciers and melting ice:
- Glaciers throughout the world are shrinking an dretreating. It is estimated that some may disappear completely by 2035. Artic sea ice has thinned by 65 per cent since 1975 and in 2014 its extent was at an all-time low
Rising sea level:
- According to the Intergovernmental Panel on Climate Change (IPCC), the average global sea level has risen between 10 and 20cm in the past 100 years. There are two reasons why sea levels have risen:
- When temperatures rise and freshwater ice melts, more water flows to the seas from glaciers and ice caps
- When ocean water warms it expands in volume- this is called thermal expansion.
Seasonal changes:
- Studies have suggested that the timing of natural seasonal activites such as tree flowering and bird migration is advancing. A study of bird nesting in the mid-1990s discovered that 65 species nested an average of 9 days earlier than in the 1970s.
what is the greenhouse effect
Greenhouse effect-
- Atmosphere allows most of the heat from the sun (short-wave radiation) to pass straight through it to warm up the Earth’s surface. However when the Earth gives off het in the form of long-wave radaition, some gases such as carbon dixoide and methane are able to absorb it. These gases are called greenhouse gases
- the greenhouse effect keeps the earth warm
Greenhouse Gases:
- carbon dioxide
- methane
- nitrous oxides
Atmosphere:
- Particles - e.g. dust
- Gases - e.g. nitrogen
- Liquids- e.g. water
the human impact
CO2 - accounts for an estimated 60% of the enhanced greenhouse effect. Global concentration of carbon dioxide has increased by 30% since 1850:
- Burning fossil fuels (oil, gas, coal) in industry and power stations to produce electricity
- Car exhausts
- Deforestation and the burning of wood
Nitrous Oxides- very small concentrations in the atmosphere are up 300 times more effectuve in capturing heat than carbon dioxide:
- Car exhausts
- Agricultural fertilisers
- Power stations producing electricity
- sewage treatment
Methane- very effective un absoring heat. Accounts for 20% of the enhanced greenhouse effect:
- Decaying organic matter in landfil sites and compost tips
- Rice farming
- Farm livestock
- Burning biomass for energy
Renewable energy
- Burning of fossil fuels contributes 87% of all human-produced carbon dioxide emissions
- The rest comes from land use changes:
- deforestation (9%)
- industrial processes (4%) e.g. making cement
Alternative sources of energy:
Hydro-electricity, nuclear, solar/winds and tides
– These do not emit large a,ounts of carbpn dioxide, the UK aims to produce 15% of energy by renewables
carbon capture
carbon capture and storage uses technology to capture carbon dioxide from the use of fossil fuels in electricity generation and industrial processes. Once captured, the carbon gas is compressed and transported by pipeline to an inection well. It is injected as a liquid into the ground to be sotre dun geological resevoirs
- catches 90% of carbon that would otherwise enter the atmosphere
tree planting
These act as carbon sinks, removing carbon dioxide from the atmosphere by photosynthesis. The moisture, which they release, have a cooling effect producing more clouds, which reduces the solar radiation
Plantation forests can absorb carbon dioxide at a faster rate than natural forests, they can do so effectively for up to 50 years
international agreements
Climate change is a global issue and requires solutions
Carbon emissions spread and affect everybody
Kyoto Protocol- 2005
– over 170 countries agreed to reduce carbon emissions by an average of 5.2% below their 1990 levels by 2012. Only the USA and Australia refused to sign (of all the major greenhouse gas emitters)
Copenhagen accord- 2009
– pleged to redyce emissions with financial support for developing nations to help the cope with the impacts of climate change- no legal binding agreement
Paris agreement- 2015
- 195 countries adopted the first ever universal and legally binding global climate deal
- to peak greenhouse gas emissions as soon as possible and achieve a balance between souces and sinks of greenhouse gasses in the second half of this century.
- to keep global temperatures increase below 2 degrees celsius and limited to 1.5 dc above pre-industrial levels
- review progress every 5 years
- US$100 billion a year to support climate change intitiatives in developing countries by 2020, with further finance in the future.
Climate change effects on argriculture systems
- patterns of rainfall and temperature will change
- extreme weather events such as heatwaves, droughts and floods will become more common
- the distribution of pests and diseases will change
Managing impacts of climate change
agriculture
- Agricultural adaptation farming:
– Low latitudes:
Southern Africa’s maize crop could fall by 30% by 2030 and the production of rice in South Asia by 10%
– Middle latitude:
Warmer climates in Europe and North America could lead to an increase in production of crops such as wheat. In the UK, mediterranean crops such as vines and olives may thrive
ADAPTATION (Gambia)-
introducing drought resistant crops, new irrigation systems, shade trees toprotect seedlings, new cropping patterns and educating farmers in water harvesting techniques
Managing water supplies- especially in the Himalayas
- Climate change is causing more droughts and floods. Unreliable rainfall and periods of water shortage needs careful management.
- Climate change in the future, will afect current pattern sof water supply, impacting qunatity and quality. Rural parts of poorer countries are most likely to be affected.
- Millions of people in Asia depend on rivers fed by snow and glacial melts for domestic and argricultural water supplies.
- In the Himalayas, 16,000 glaciers are receeding rapidly due to global warming. This threatens long term security of water supplies in the region
- Artificial glacier project (creating glaciers) will supply water to villages in Ladakh, India. Water is collected in winter through a system of diversion canals and embankments and it freezes. When the ‘glacier’ melts in spring it will provide water for the local villages
Reducing risk of rising sea levels - including Maldives
Average Sea levels have risen by 20cm since 1900, by 2100 swa levels are expected to rise by a further 26-82cm. This will flood important argricultural land in countries such as Bangladesh, India and Vietnam.
- As sea levels rise, rates of coastal erosion will increase. fresh water supplies will become contaminated by daltwater and coastal areas will be prone to damage from strom surges
Managing rising sea levels in the Maldives:
- group of tiny islands in the India Ocean, about 500km south-west of India.
- highest point of the islands is just 2.4m
- some climate models suggest that the islands may be uninhabitable by 2030 and submerged by 2070
- the 380,000 inhabitants have a very uncertain future as sea levels rise
ADAPTATIONS-
- Construction of sea walls- a 3m sea wall is being constructed around the capital Male with sandbags elsewhere
- Building houses that are raised off the ground on stilts
- Restoration of coastal mangrove forests- their tangled roots trap sediment and offer protection from storm waves
- Construction of artificial islands up to 3m high so that people most at risk could be relocated
- Ultimately the entire population coud be relocated to Sri Lanka or India
what are the global impacts of climate change?
- stronger tropical storms
- higher global temperatures affect food production and water supply
- ENVIRONMENTAL IMPACTS, such as desertification
- wildlife at risk as habitats and ecosystems at risk
- rising sea levels threaten llow-lying coastal areas
- ECONOMIC IMPACTS, such as lower crop yields and damage to infrastructure
- increased rsk of natural hazrds, such as droughts and floods
- more heat-related ilness and disease such as Malaria
Natural causes of climate change
Orbital- the earth moves closer and further away from the sun as it orbits. Meaning the climate is warmer, when the sun is close to the sun and vice versa
Solar Activity- the sun contributes to warming up the earth. The higher the solar intensity means higher temperatures and lower with less solar intensity.
- sunspot acitivty at maximum means the sun gives off more heat
Volcanic activity- volcanic ash can block out th sun, reducing temperatures on the earth. Droplets which are the result of sulphur dioxidie to sulphuric acid reflect like mirrors, reflect the radiation from the sun.
Mt Tambra- it is known for having an extreme eruption and it led to glaciers melting, starvation, freezing and spread in disease. Around 50m tonnes of sulphur dioxide was released into the atmosphere, which has a cooling effect, so the Earth began to cool down.
- caused average temperatures to go down by 0.4 - 0.7 dc
Human causes of climate change
Burning fossil fuels- carbon dioxide
- causes an increase in levels of greenhouse gases in the atmosphere
Deforestation- trees absorb carbon dioxide to maintain the carbon dioxide balance in the atmosphere. Deforestation means less trees to absorb it therefore the CO2 balance is not being maintained
Car exhaust- nitrous oxides
Car exhausts give off nitrous oxides and other greenhouse gases. They trap heat meaning an increase in temperatures, when they are released into the atmosphere
Methane- CH4
It has warming effects meaning when released it warms up the earth when released into the atmosphere.
