Climate Change

Methods used to reconstruct the Earth's past climate

• Sea-floor sediments
• Ice cores
• Lake sediments
• Tree rings
• Fossils

Quaternary period

Spans the last 2.6 million years, consists of fluctuations between glacial and inter-glacial periods

The Holocene

The current geological period, began at the end of the last glacial period roughly 11,700 years ago

The Anthropocene

The theoretical geological period in which human activity has significantly influenced climate patterns

Milankovitch cycles

Obliquity - tilt of the Earth's axis, influences seasons and temperatures

Eccentricity - how elliptical Earth's orbit of the Sun is, closer to the Sun means higher temperatures

Precession - the Earth's 'wobble' on its axis, Earth gyrates on its axis like a spinning top

Natural causes of climate change

• Milankovitch cycles
• Volcanic eruptions
• Solar output
• Ocean circulation
• Tectonic plate action

How do tectonic plates affect climate change

Continental plates that are rising to higher altitudes will cause the expansion of permanent ice cover - this increases the albedo effect

How does ocean circulation affect climate change

Ocean currents influence the Gulf Stream which causes changes to the global distribution of warm air

Evidence that the world has warmed since the late 19th century

• Increase in global temperature
• Shrinking valley glaciers and ice sheets
• Rising sea levels
• Decreasing snow cover and sea ice

How much has sea level been rising by per year

1.0 - 2.5 mm/year

How does sea ice affect climate change

A reduction in sea ice means more solar energy is being absorbed by the ocean, this increases sea temperature and causes further ice melt - positive feedback loop

Anthropogenic causes of climate change

• Increased emission of greenhouse gases
• Deforestation
• Farming
• Rising global population

UK carbon dioxide emissions in 1900

114,558 (1000s tonnes of carbon)

China carbon dioxide emissions in 1900

26 (1000s tonnes of carbon

When did the UK's industrial revolution begin

Late 18th to early 19th century

The UK's annual carbon emissions peaked in what year, and by how much has it fallen since

Peaked in 1971, fallen by one third

Factors influencing the UK's reduction in carbon emissions

• Development of renewable and nuclear energy sources
• International agreements
• Improvements in energy conservation and efficiency
• The shift away from coal as the primary fuel electricity generation to natural gas

UK 2013 carbon emissions

467,500 (1000s tonnes of carbon)

China 2013 carbon emissions

2,490,000 (1000s tonnes of carbon)

When did China's industrial revolution begin

Late 1970s after trade liberalisation was introduced

Reasons why China's carbon emissions are so high

• Unhampered by international protocols such as Kyoto
• Largest population in the world
• Rapid economic development
• Very few environmental regulations

Case study for the effect of ACs on climate change

UK

Case study for the effect of EDCs on climate change

China

Explanation of the 'hockey stick' graph

Relatively low carbon emissions for a long time then rapid growth in a very short period of time - creates a hockey stick shape

When was the Kyoto protocol formed

1997

What were the aims of the Kyoto protocol

• Reduce GHG emissions by at least 5% by 2012
• Reduce GHG emissions by at least 18% by 2020
• Limit global temperature increases to no more than 2 degrees Celsius

Negative feedback loops relating to rising carbon dioxide levels

Expansion of forests - tree line advances poleward, increases absorption of carbon

Increased cloud cover - increase in evaporation leads to more clouds, increased albedo effect

Increased aerosols - aerosols reflect solar radiation, reduces temperatures

Positive feedback loops relating to rising carbon dioxide levels

• Increased evaporation (water vapour GHG)
• Reduced albedo from ice
• Melting permafrost
• Increased ocean acidity
• Decreasing forest cover

Environments most vulnerable to climate change

• Tundra
• Mountains
• Hot semi-arid environments
• Rainforests
• Coasts

Mitigation strategies to cut GHG emissions

• Improve energy efficiency and conservation
• Fuel shifts and low-carbon energy sources
• Eco-friendly building designs
• Carbon capture and storage
• Geoengineering
• Reforestation and forest conservation

Adaptation strategies to reduce vulnerability to climate change

• Coastal residential retreat
• New farming techniques
• More efficient water supply and usage
• Improve education and awareness
• Hard engineering structures
• Improve access to medication

Case study for LIDC at risk from climate change

Bangladesh

Case study for AC at risk from climate change

Australia

What percentage of Bangladesh floods each year

70%

What is the average elevation in Bangladesh and what percentage of the land there is just 1m above sea level

Average elevation is 4-5m, 10% is 1m above sea level

Impacts of climate change on Bangladesh

• Increased level of flooding
• Increased number of cyclones
• Salination of farmland, too acidic for crops
• Damage to mangrove forests, natural protection
• Spread of water-borne diseases

By 2100, how much farmland in Bangladesh could be to highly salinized for cultivation

600,000 ha

In the past 25 years, what percentage of deaths from tropical cyclones have occurred in Bangladesh

60%

Adaptation strategies in Bangladesh

• $2 billion investment in flood embankment projects, loan from the World Bank
• Improve the 3500km of dykes
• Improvement to storm surge warning systems
• Cyclone and flood shelters built
• Local communities encouraged to protect the mangrove forests
• Improved agricultural techniques
• Research programme into water-borne and vector-borne diseases

Why doesn't Bangladesh use mitigation strategies

They regard mitigation and GHG emission reduction to be the responsibility of developed countries

Impacts of climate change on Australia

• Increase in the number of natural disasters
• Rising sea level has reduced tourism, amenity value reduced
• Sea acidification has bleached the Great Barrier Reef
• Coastal squeeze
• Increased number of droughts
• Extreme heat leads to health problems
• Increase in bush fires

How much do natural disasters cost the Australian economy per year

$4.5 billion per year

Cyclone Yasi in 2011 reduced Queensland's GDP by how much

$4 billion

Mitigation and adaptation strategies in Australia

• 5-25% reduction in carbon emissions by 2020 following the Copenhagen summit
• Developed a cap and trade scheme
• Construction of sea walls and dams
• Relocation of coastal houses
• $9 billion investment programme to develop new water resources and improve water efficiency
• Disaster-response management will be upgraded

What are carbon permits and caps

Carbon permits act as a 'quota' for governments and companies limiting the amount of carbon that they can emit. Permits can be bought and sold to other governments or companies