Climate Change Flashcards

Long-term evidence for climate change

1. Ice cores: ice cores contain layers of snow that have formed over thousands of years. As each layer forms, it traps bubbles of gas from the atmosphere during that time. Scientists can measure gas concentrations in those bubbles. The amount of carbon dioxide in those bubbles can tell what the temperatures were like during those years.

2. Tree rings: Tree growth rings are added each year that the tree is growing. The thicker the ring, the hotter and wetter it was that year.

3. Fossils: Some plants and animals can only live in certain climates.

   Fossils of these plants and animals discovered in different places can be dated.

   This indicates the climatic conditions of certain areas during those dates.

4. Evidence from artwork: Images that were painted in the past can give clues to past climate conditions. ‘The Little Ice Age’ artwork shows how London used to become so cold The Thames would freeze over and it would hold fairs.

Recent evidence for climate change

1. melting ice sheets: There is 50% less Arctic sea ice than there was 30 years ago.

2. sea level rise: Warming temperatures will lead to melting ice which will increase sea levels. also thermal expansion: oceans will expand as they become warmer

3. seasonal changes: Changes in the seasons of temperatures and rainfall can change land cover and the behaviour of animals.

4. melting glaciers: glaciers are melting and retreating

5. temperature

Warmer periods also called…

interglacial periods

colder periods also called…

glacial periods

natural causes of climate change

1. sunspots

There is a cycle to the amount of energy given off by the sun.

The amount of energy is measured by counting sunspots (black spots on the sun’s surface)

The more sunspots, the more energy the sun gives off and therefore the warmer the Earth.

Sunspots increase from a minimum to a maximum every 11 years.

Example: The Little Ice Age (1645-1715) was when sunspots were at a minimum.

However, sunspots are currently at a minimum and so cannot be responsible for recent changes

2. volcanic winters

Violent volcanic eruptions blast huge quantities of ash, gases and liquids into the atmosphere.

Volcanic ash can block out the sun and reflect the radiation back to space causing the Earth to cool temporarily  – ‘volcanic winter’.

When sulphur dioxide is released in an eruption, it mixes with water vapour and produces an aerosol which reflects the sun’s heat energy away from the Earth.

3. changes in the Earth’s orbit

The Earth’s journey around the sun changes and so changes the amount of energy the Earth receives. These are powerful enough to cause the huge changes between glacial and interglacial periods. They are called Milankovitch Cycles.

more circular orbit = closer to the sun, interglacial (10,000 years)
elliptical orbit = move further from the sun, glacial (100,000 years)

the greenhouse effect

Human causes are closely linked to the greenhouse effect

The sun’s radiation enters the atmosphere and hits the Earth. Some is absorbed and some is reflected back out into space. Carbon dioxide in the atmosphere absorbs some of the heat and creates a warm blanket around the Earth which increases temperature. The enhanced greenhouse effect is caused by humans. This is where human activities have increased the levels of carbon dioxide in the atmosphere. This increases the amount of the sun’s radiation which is absorbed in the atmosphere which has increased temperatures.

Human activities that have increased the levels of greenhouse gases in the atmosphere

Fossil Fuels	Fossil fuels (coal, oil and gas) account for 50% of global greenhouse gas emissions. largest contributor When they are burnt, carbon dioxide is released into the atmosphere. They are used for things like transport, building, industry and heating homes.  As the average wealth of the world increases and LIC countries begin to develop, the demand for fossil fuels increases for energy and so greenhouse gas emissions increase. This also releases nitrous oxide (300x more effective at capturing heat)
Agriculture	Agriculture accounts for 20% of greenhouse gas emissions, especially methane from cattle and rice fields. As population increases and demand for food increases, more greenhouse gases are emitted.  Methane is produced from cows during digestion and from microbes when they decay organic matter under the water in rice fields. As countries develop, their demand for meat increases which increases emissions. Fertilisers can also release nitrous oxide
Deforestation	Deforestation is the clearing of forests on a huge scale. Forests are a carbon sink which means they store carbon. Less trees = more carbon dioxide. Also when trees are brunt the stored carbon is released.  Trees absorb carbon through the process of photosynthesis which reduces the amount of carbon dioxide in the atmosphere.

Social /economic Impacts of climate change

• Increased risk of diseases such as skin cancer and heat stroke as temperatures increase

• water scarcity made worse. future conflicts over water

• Extreme weather can become more common and cause cost increases for monitoring and prediction

• climate refugees

• Skiing industries will decrease in the Alps as snow cover decreases

• increased repair and insurance costs.

• agriculture: less water for farming, stronger storms and more floods to damage crops

• coastal areas that will be flooded

• Less ice in the Arctic Ocean increases shipping and extraction of gas and oil

• increased tourism in areas such as UK

environmental impacts of climate change

• Sea level rise causes flooding and coastal erosion with increased cost for defences

• Ice melts so wildlife declines such as polar bears on Arctic sea ice

Mitigation strategies meaning

Mitigation strategies aim to reduce the effect of climate change by focusing on the cause of the problem. These tend to be more global

adaptation strategies meaning

Adaptation strategies respond to the impacts of climate change and reduces population vulnerability. These tend to be more local

Mitigation

Carbon Capture	This takes carbon dioxide from areas it is being emitted (factories and electricity generation) and stores it underground in a liquid. There is an impermeable ‘cap’ rock to prevent it from escaping. It can capture up to 90% of the carbon being emitted. The UK is a world leader in carbon capture and storage It cannot take carbon dioxide directly from the atmosphere that is already there, it is expensive and does not promote renewable energy.
Alternative Energy Production	These are different to fossil fuels and more renewable They include wind, solar, wave, tidal, geothermal energy. This will be good because burning of fossil fuels contributes 87% of all human produced carbon dioxide They do not release carbon dioxide and will last longer and are becoming cheaper over time. They are expensive to start up and can be unreliable (depend on the sun for example)
Planting Trees	This is also called afforestation. Planting trees helps to remove carbon dioxide through photosynthesis (they are a carbon sink) It could increase carbon storage by 28%. They also release moisture which has a local cooling effect and produces clouds which reduces incoming solar radiation. However, land may be limited and must be protected. The replanting of trees must outpace that of deforestation.
International Agreements	International agreements encourage countries to take responsibility to reduce their carbon dioxide emissions. They work best when they are legally binding (Paris 2015 agreement) Paris 2015 agreement was between 195 countries and was the first legally binding deal. However, in 2017, USA withdrew from the agreement. Financial support can be given to LICs However, agreements that are not legally binding can have little effect, they may not be enough and it can be hard for countries to agree targets.

Adaptation

Changes in Agricultural Systems	These are needed to deal with changes in rainfall and temperature patterns, more extreme weather and the spread of pests and disease. Production may need to move location where climates are now suitable Irrigation will be needed more to water farms and will put pressure on water supplies. These changes are more difficult for poorer farmers and who are most likely to be affected Some things they can do are Introducing drought resistant varieties Educated farmers Shade trees can be planted to protect smaller plants New planting patterns and times New irrigation systems
Managing water supplies	Water supplies are facing increased pressure and stress from changing rainfall patterns. build reservoirs transferring water using greywater desalination Areas where there is water stress and deficit may face conflict and needs political stability to manage it
coastal defences	sea levels are expected to rise by at least 30cm which will increase coastal flooding and erosion that people need to be protected from building sea walls building houses on stilts relocating populations replanting mangrove forests

judgement: mitigation & adaptation

Both methods are necessary.

If only adaptation methods are carried out, the problem will keep getting worse, new adaptation methods will be consistently necessary and this will end up costing a huge amount of money. Some also argue there is a limit to the changes that we are able to adapt to.

Mitigation is necessary to solve the problem. However, the effects from current changes will still be felt in the future so adaptation will also be needed in the short term.

It is arguable that mitigation overall will be better to stop the problem, but governments must budget for short term adaptation due to current changes than to only adapt which will not solve the problem and will cost more and cause huge problems in the long term.