2.A Flashcards
evidence the earth has warmed since late 19th century - Increases in surface, atmospheric and ocean temperature
Consistent rise in global land and ocean temperatures in 20th century – powerful evidence of climate change.
- rising temperatures have been a dominant trend over 135 years – several anomalies have occurred 1880-2014
evidence the earth has warmed since late 19th century - Shrinking of valley glaciers and ice sheets
Glaciers grow and shrink in length width and depth – sensitive to temperature and precipitation that accompany climate change. The rate of their growth/decline serves as an indication of regional and global climate change.
We can use high resolution satellites images to track the size and movement of glaciers. We can compare these satellite images with historical maps and determine the glaciers advance or retreat – help reveal the short and long term trends.
In Alps valley – 80-96% may shrink by end of century. Between 1961 and 2005 thickness of small glaciers decreased on av. 12 m .
evidence the earth has warmed since late 19th century - rising sea level
Since 1900s av. Rise = 1.0-2.5 mm/year. Two processes account for rising sea level = thermal expansion of the oceans as the words climate warms and the melting of land based ice sheets and glaciers. Rate has increase to 3mm – trend will continue
evidence the earth has warmed since late 19th century - Increasing atmospheric water vapour
As a result of land use change and globalisation – c02 going into the atmosphere is causing it to warm therefore water vapour occurs doubling the impact of C02 - climate get warmer and accentuates the output. – creating a positive feed back loop
Estimated that for every 1’c increase - levels of WV double
evidence the earth has warmed since late 19th century - Decreasing snow cover
satellite measurements reveal a decline in spring snow cover of 2 % per decade since 1966 in NH.
- this change has an impact in climate - snow has a high albedo - reflecting 60-70% of incomiing radiation compared to 20% fro soil and veg
– dimihsing snow therefore increases absorption of radiation.
- With suns energy used to wear the ground rather than melt the snow, air temperatures rise. - this created a positive feedback - explains rapid warming
evidence the earth has warmed since late 19th century - decreasing ice cover
- sea ice is frozen water that floats on ocean surface - in winter sea ice covers 20 million km2 in summer this shrinks to around 6 million
- since 1979 - satellite monitoring began - extent an dvilume of sea ice has decreased on av 8% - this means rmore solar energy radiation absorbed by ocean - raising air temperatures more rapid melting occurs
Why are anthropogenic greenhouse gas emissions increasing since pre-industrial era? - Land use changes:
- 1/3 GHG emissions come from this and the emissions of carbon from deforestation, drained wetlands and cultivated soil. Today 40% of the land surface is taken up by agriculture while up to 25% of the worlds forest has been lost since 1700s.
Effects SRO = therefore local flooding and 17x quicker than normal – decrease NPP and removes a major carbon sink.
Why are anthropogenic greenhouse gas emissions increasing since pre-industrial era? - Wealth/standard of living changing:
An increasingly wealthy pop. Has a larger carbon footprint currently the US has the largest in the world with an average household producing about 50 tonnes C02 per years. 5x greater than global average.
Why are anthropogenic greenhouse gas emissions increasing since pre-industrial era? - Population Growth:
A greater number of people in would – increase GHG
Why are anthropogenic greenhouse gas emissions increasing since pre-industrial era?
Demand for energy:
- Manufacturing industries, power stations and transport burn fossil fuels – 87% of the words energy production is from burning these fossil fuels – produces C02. contributes to ¾ of worlds atmospheric carbon since 1750s
- In increasingly globalised world more people are flying on long haul flights and more goods are transported. Planes have a carbon footprint 30x greater than high speed trains.
case study AC - ontribution of UK to greenhouse gas emissions over time - HISTORY
Broad History –
- service sector dominates the UK economy – cont. 80% of GDP
- London is the worlds largest financial centre and Britains aerospace industry is the 2nd largest
- pharmesuetical – 10th largest
-economy boosted by North sea oil and gas production – reserved estimated 2.8 billion barrels in 2016
case study AC - ontribution of UK to greenhouse gas emissions over time
18th century – first country to industrialise
19th century
– dominant role in global economy – 9.1% of world’s GDP in 1870 – from late 19th – 2nd industrial revolution was also taking
Place in USA and german empire – presented increase in economic challenge for uk
- not until early 19th that industrialisation of coal took off – significant emissions of co2 were results, from burning coal –
first country to industrialise South Wales, Bristol
– decrease of oil and coal in 1890s – due to economic recession and widespread unemployment
20th century
- 1920s – abrupt decline in emissions due to miners strike and general strikes
- 1940s – cost of WW1/2 further weakened Uks relative position.
- 1970s - Uk emission peaked largely – since then annual emissions habe decreased by 1/3 – reasons:
Improvement in energy conservation through energy efficient homes, factories and offices
International obligations and legally binding reductions in co2 emissions
Developent of nuclear power stations and renewable energy resources – 1980s
Shift from coal as primary fuel for electricity generation to cheaper natural gas
case study AC - ontribution of UK to greenhouse gas emissions over time- NOW
21st century
- remains a global power and influenced role in world economy
Now total emissions have dipped due to globalisation, agreements and service sector
Case Study – EDC – contribution of China to greenhouse gas emissions over time
Facts –
Chinas economic developemtent and industrialisation – made possible by massive energy consumption – most of energy comes from huge indigenous reserves of coal which increases carbon emissions
20th century
- early – China had a rural economy and low number of people living in cities
- 1970s – countries economy – overwhelming rural – dependant on biofuels
- 1978 – situation changed ramatically – abruot U turn of policies by china’s leaders moved country away from strict command economy and so it embraced the free market – economic liberalisation stimulated international trade and FDI – China emrged as a major player in global economy – economic growth based on export and led manufacturinhg
- industrialsiation accompanied large urbanisation - millions of people migrated from rural to urban areas in last 40 years – largest population movement in history
Case Study – EDC – contribution of China to greenhouse gas emissions over time - TODAY
TODAY
- china consumes almost as much coal as the rest of the world – 2006 – overtook USA as worlds largest emitters of carbon
- unhampered by international protocols like KYTO, emissions increase2 and a hald in 2000 – 2014
-China controls 12% of worlds exports compared to 1 % in 1970s
- although emissions rates have slowed – coal still provides nearly 2/3 of china’s energy, China aims to reduce co2 emissions by 40% period of 2005 – 2020 – little chance of success
