1. 2. Anthropogenic Greenhouse Gas Emissions
1.1. Enhanced Greenhouse effect
1.1.1. What is it
1.1.1.1. Since early 19th century the volume of earths GHG has increased rapidly
1.1.1.1.1. Most striking change is the increase in CO2 of about 1/3
1.1.1.2. As the climate has warmed change has been amplified
1.1.1.2.1. Increases in evaporation and therefore water vapour
1.1.1.3. Advanced greenhouse effect increases absorption of longwave radiation
1.1.1.3.1. Raising global temperatures
1.1.2. Main greenhouse gasses
1.1.2.1. 60% water vapour
1.1.2.1.1. 20% Carbon dioxide
1.1.3. Change in greenhouse effect over time
1.1.3.1. CO2 accounts for 3/4 of all anthropogenic GHG emissions
1.1.3.1.1. Before 1800 its concentation in the atmosphere was fairly stable
1.1.3.2. Methane
1.1.3.2.1. Atmospheric concentrations of methane are much smaller
1.2. Why have anthropogenic emissions increased?
1.2.1. 1. Huge demand for energy due to industrialisation and technology advances
1.2.1.1. Fossil fuels still supply 87% of worlds energy
1.2.1.1.1. Massive increase from the 1960's as india and china industrialise
1.2.1.1.2. Decline of coal
1.2.1.2. Change in usage
1.2.1.2.1. In 1960 Europe produced the most CO2
1.2.1.2.2. Peak production of CO2 in north america is 6 gigatones
1.2.1.2.3. Europe's usage declined in line with regional shifts
1.2.1.2.4. Statistics to prove change in usage
1.2.1.3. Cement production
1.2.1.3.1. Breaks limestone rocks, releasing co2 into atmosphere
1.2.1.3.2. Every 1000kg cement produced 900kg co2
1.2.1.4. Air traffic
1.2.1.4.1. Emits nitrous oxides
1.2.2. 2. Massive global population growth and rise in living standards
1.2.2.1. Agriculture
1.2.2.1.1. 1/4 of all greenhouse gases come from agriculture
1.2.2.1.2. 12% of global methane comes from rice
1.2.2.1.3. Soy beans production for animal food results in more than 80% deforestation in Brazil
1.2.3. 3. Land use change, especially deforestation and draining of wetlands for food production
1.2.3.1. Deforestation
1.2.3.1.1. Area the size of Italy lost each year
2. 3. Case Study: UK
2.1. Changing balance in coal
2.1.1. Coal dominated UK main energy source for much of 20th century
2.1.1.1. Peaked in 1916 with 137 million tonnes
2.1.2. Until 1970 the reliance on coal and expanding economy led to carbon emissions increasing annually
2.1.2.1. However when GDP and economic activity fell (1921 miners strike) so did emissions
2.1.3. Why was Coal used in Britain
2.1.3.1. Easy to access in Britain
2.1.3.1.1. Provided 3 times more energy than wood
2.1.3.2. Accessing coal by the sea led to ability to ship coal cheaply to london
2.1.3.2.1. Coal sparked industrial revolution in 1800s and in that century coal emissions increased 16 fold
2.1.4. Coal emissions peaked in 1971 since then fallen by 1/3
2.1.4.1. Due to shift from coal for electricity to gas
2.2. Developments in energy in the UK Changing balance of anthropogenic emissions
2.2.1. Natural Gas
2.2.1.1. 47% of gas comes from domestic production, 31% from pipelines
2.2.1.1.1. Nord stream pipeline transports 55 billion cubic metres of natural gas
2.2.1.2. Why is it being used more
2.2.1.2.1. Historically it has been one of the cheapest forms of energy with high availability
2.2.1.2.2. Gas burns cleaner than coal
2.2.2. Nuclear usage
2.2.2.1. Development of nuclear power began in the 70s and 80s
2.2.2.1.1. Britains nuclear capacity peaked in 1997
2.2.2.2. Today Britain generates 6.5 gigawatts from nuclear energy
2.2.2.2.1. 26% of Britains power
2.2.2.3. However in 2024 there will only be 3 operational powers stations and 2 by 2030
2.2.2.3.1. Has been in decline since 1997 due to high costs of construction and maintenance
2.2.3. Renewables
2.2.3.1. Britain installed capacity for wind and solar energy from the 90s
2.2.3.1.1. Now at 35 gigawatts a year
2.3. Why has UK emissions decreased
2.3.1. Improved energy conservation in energy efficient homes, offices and factories
2.3.1.1. 84% of new builds in the UK are in bands A and B energy efficiency rating
2.3.1.2. £6 billion decarbonisation of British homes programme from government
2.3.2. International Obligations
2.3.2.1. 2050 Target
2.3.2.1.1. UK gov to reduce GHG emissions by at least 100% of 1990 levels (net zero)
2.4. Current state of UK emissions
2.4.1. In 2014 UKs total emissions were 35% below 1990 levels
2.4.1.1. UK co2 levels were 29% less on 1990 levels
3. 1.Evidence of warming since the late 19th century
3.1. Visual evidence the Earth is warming
3.1.1. Glacier and ice sheet melting
3.1.2. Sea level rise
3.1.3. Temperature increase
3.1.4. Increase in atmospheric water vapour
3.2. Climate records began in 1880
3.2.1. Since then we have seen temperatures increase by 0.9 celcius
3.3. Increases in Global temperature
3.3.1. Beginning of 21st century has seen rise in temperature
3.3.1.1. 2023 was the warmest year for mean global land and ocean temperatures since records began
3.3.2. 2016 was the 40th consecutive year of an increase in global temperatures
3.3.2.1. 9 of the 10 warmest years on record have occured since 2000
3.3.3. How does rising temperature provide evidence of climate change
3.3.3.1. Death Valley
3.3.3.1.1. 54.4 degrees, hottest temperature recorded on the 9th July 2021
3.3.3.2. Arctic has warmed 3X quicker than planet as a whole from 1971-2019
3.3.3.2.1. Averages temperatures in arctic rose by 3.1 degrees in the same period
3.4. Shrinking Valley Glaciers and Ice Sheets
3.4.1. In the alps it is predicted that valley glaciers may shrink upwards of 80% by the end of century
3.4.1.1. In 1850, 150 glaciers observed in Glacier national park montana, by 2010 only 25 observed
3.4.2. Between 1961 and 2005 the thickness of small glaciers worldwide decreased by an average of12m
3.4.2.1. Polar melting contributes to 1mm sea level rise a year
3.4.3. Different effects of warming on Greenland and antarctica
3.4.3.1. Antarctica
3.4.3.1.1. Warming of oceans
3.4.3.1.2. Melting of antarctica
3.4.3.2. Greenland
3.4.3.2.1. Melting of ice surface due to surface temperature
3.4.4. How does melting glaciers provide evidence of climate change
3.4.4.1. Himilayan glaciers may lose 75% of their mass by 2100
3.4.4.1.1. Caused by an Abnormal rise in temperature
3.4.4.2. Antarctica is losing mass at an average rate of 150 billion tonnes per year
3.4.4.2.1. Greenland at 270 billion tonnes a year!
3.5. Rising sea levels
3.5.1. What causes sea level rise
3.5.1.1. Thermal expansion
3.5.1.1.1. Expansion of sea water as it warms
3.5.1.2. Added water from melting land ice
3.5.2. Since 1900 the average rise was 1-2.5 mm a year
3.5.2.1. Currently this has increased to 3mm a year and is predicted to grow exponentially
3.5.3. How does rising sea levels provide evidence of climate change
3.5.3.1. Sea level in last interglacial (125,000 years ago) was 10 metres above current level
3.5.3.1.1. During period the polar regions were warmer then today
3.5.3.1.2. Suggesting long periods of warmth will cause significan loss of land ice and increase sea levels
3.5.3.2. Projected that sea levels may rise by almost a metre (0.8m) by 2100
3.5.3.2.1. Best case scenario
3.6. Decreasing snow cover and sea ice
3.6.1. Spring snow cover has declined by 2% per decade since 1966
3.6.1.1. Snow has high albedo reflecting 95% of solar radiation
3.6.1.1.1. Hence the decrease of snow cover would increase absorption of solar radiation
3.6.2. Changing in Arctic sea ice
3.6.2.1. Normally, Frozen ocean water surface covering 20 million square kilometres in winter shrinks to 6 million in summer
3.6.2.1.1. Since 1979 arctic sea ice decreased in extent and thickness
3.6.2.1.2. In September 2012 area of arctic sea ice shrank to new minimum of 3.63 million kilometres squared
3.7. Increasing Atmospheric water vapour
3.7.1. Scientists suggest water vapour has a heat amplifying effect
3.7.1.1. Potent enough to double climate warming caused by increased levels of co2 in the atmosphere
3.7.1.2. Water vapour traps huge amounts of energy radiated from earths surface
3.7.1.2.1. Creates a natural greenhouse effect
3.7.1.3. Amount of water vapour in atmosphere is related to temperature and rates of evaporation
3.7.1.3.1. So in a warmer world there will be more atmospheric moisture
3.8. Extreme Events
3.8.1. Since 1950s number of record high temp events in the US has increased
3.8.1.1. Number of low temp extreme events have decreased
3.8.1.2. Between 2011 and 2013 the US experienced 32 weather events that cost $1 billion in damage
3.8.1.2.1. More intense and frequent heatwaves
3.8.2. Heatwaves
3.8.2.1. Have become more common despite many places lacking good record keeping of heal related deaths
3.8.3. Flooding
3.8.3.1. Coming as a result of climate change as glaciers melt contributing to torrential rain
3.8.3.1.1. During 2022 flooding in Pakistan a third of the country was underwater
4. 4. Case Study: China
4.1. Reasons for increasing emissions
4.1.1. Industrialisation led to urbanisation and huge rural-urban migration
4.1.1.1. Increased emissions as 75% of global co2 emissions is from cities (transport and buildings)
4.1.1.2. Urban population went from 700 million in 2011 to 914 million in 2021, approx 20 million a year!
4.1.1.3. Economic development was made possible by coal energy consumption
4.1.1.3.1. Average incomes rose from 299USD in 1980 to 12000USD in 2012
4.1.1.3.2. CO2 emissions have rised 2.5 times between 2000 and 2014 as a result
4.1.1.4. Rapid urbanisation boosts cement production with chinese cities twice the size of new york being construvted (Xiongan)
4.1.1.5. Transport emissions increase as people commute around urban areas
4.1.1.5.1. Results in construction of more coal powerstations
4.1.2. Coal Emissions
4.1.2.1. As of end of 2014 china had 62 billion tonnes of anthracite and 52 billion lignite quality coal
4.1.2.1.1. China ranks third in the world in terms of coal reserves behind US and russia
4.1.2.1.2. China has 30 years worth of reserves
4.1.2.1.3. results in mass carbon emissions
4.1.2.2. In order to keep warming below 1.5 degree global coal usage must fall 80%
4.1.2.2.1. Meanwhile china is building 40Gw worth of powerstations and planning 50Gw more
4.1.2.3. China is responsible for 46% of global coal production
4.1.2.3.1. Now accounts for 45% of all coal based electricity generated around the world increasing from 37% in 2010
4.2. Changing trends in carbon emissions
4.2.1. December 1978 chinese economy changed to an 'open door' policy
4.2.1.1. President Xiaoping realised china needed western technology for development
4.2.1.2. Economic growth encouraged with four economic zones created in southern china
4.2.1.2.1. These zones were used to incentavice foreign business to invest
4.2.2. 2001 china joined world trade organisation
4.2.2.1. Ensured it economy continued to flourish