Long term climate changeLong term climate change

Climatic periods since the Climatic periods since the Pleistocene Ice Age in the UKPleistocene Ice Age in the UK

Pre Boreal 10,300 BPPre Boreal 10,300 BP Change from Tundra to continental.Change from Tundra to continental.

Original cold and wet but becoming Original cold and wet but becoming warmer and drierwarmer and drier

Boreal 9,000 BPBoreal 9,000 BP Becoming warmer and drier: a typical Becoming warmer and drier: a typical continental climatecontinental climate

Atlantic 7,500 BPAtlantic 7,500 BP Climatic optimum warm and with Climatic optimum warm and with slightly higher rainfall slightly higher rainfall

Sub Boreal 5,000 BPSub Boreal 5,000 BP Becoming colder in winter, rainfall Becoming colder in winter, rainfall slowly increasing. Some ice advanceslowly increasing. Some ice advance

Sub Atlantic, 2,500 BPSub Atlantic, 2,500 BP

Little climatic optimum 1300 – 1100ADLittle climatic optimum 1300 – 1100AD

Little Ice Age 1550 – 1859 ADLittle Ice Age 1550 – 1859 AD

Today Global warmingToday Global warming

Temp fluctuationsTemp fluctuations

Warmest since Atlantic, wine in UK Warmest since Atlantic, wine in UK VikingsVikings

Thames freezes. FamineThames freezes. Famine

Temps. Slowly increasingTemps. Slowly increasing

Evidence for climate changeEvidence for climate change

Pollen analysis;Pollen analysis;

Dendrochronology;Dendrochronology;

Ice core analysis;Ice core analysis;

Radiocarbon dating;Radiocarbon dating;

Coleoptera;Coleoptera;

Tephra chronologyTephra chronology

Historical records.Historical records.

Pollen analysisPollen analysis

The pollen analysis, study of vegetation The pollen analysis, study of vegetation history using the microfossils (pollen grain history using the microfossils (pollen grain and spores of size 15-50 um) and spores of size 15-50 um) The pollen is preserved in peat bogs( an The pollen is preserved in peat bogs( an anaerobic environment) and the type of anaerobic environment) and the type of vegetation can give a clue to the prevailing vegetation can give a clue to the prevailing climate.climate.But the wind can blow pollen a long But the wind can blow pollen a long distance.distance.

DendrochronologyDendrochronology

..is the dating of past events (climatic changes) ..is the dating of past events (climatic changes) through study of tree ring growth;through study of tree ring growth;

wide rings of certain species of trees were wide rings of certain species of trees were produced during warm wet years and, inversely, produced during warm wet years and, inversely, narrow rings during cold dry seasons.narrow rings during cold dry seasons.

Bristlecone PineBristlecone Pine

But trees tend to respond more to changes in But trees tend to respond more to changes in moisture than temperature.moisture than temperature.

Ice Core analysisIce Core analysis

The concentration of COThe concentration of CO22 trapped within trapped within

the ice can be measured and the the ice can be measured and the atmospheric temperature can be inferred.atmospheric temperature can be inferred.

The lower the COThe lower the CO22, the lower the global , the lower the global

temperature.temperature.

This has been done extensively in This has been done extensively in Greenland and Greenland and AntarcticaAntarctica

Radio carbon datingRadio carbon dating

Radio carbon dating determines the age of Radio carbon dating determines the age of ancient objects by means of measuring the ancient objects by means of measuring the amount of carbon-14 there is left in an objectamount of carbon-14 there is left in an objectAll living things take in carbon 12 and 14. The All living things take in carbon 12 and 14. The later decays at a known rate so when a plant later decays at a known rate so when a plant dies it starts to lose carbon 14 and so the ratio of dies it starts to lose carbon 14 and so the ratio of 12 to 14 changes.12 to 14 changes.Carbon 14 has a half life of 5,730 years and so Carbon 14 has a half life of 5,730 years and so there is a limit as to how far back this is there is a limit as to how far back this is accurate. At the moment this is about 50,000 accurate. At the moment this is about 50,000 yearsyears

ColeopteraColeoptera

Certain coleoptera beetles like specific Certain coleoptera beetles like specific climates and so a knowledge of this will climates and so a knowledge of this will help if the remains of the beetles are foundhelp if the remains of the beetles are found

TephraTephra chronology chronology

This is used to date volcanic eruptionsThis is used to date volcanic eruptions

The chemicals radioactive minerals are The chemicals radioactive minerals are dated using their half lifedated using their half life

Recent global warmingRecent global warming

The diagram shows temperature rises The diagram shows temperature rises since 1860since 1860

Tmperatures have been higher Tmperatures have been higher in the past in the past but the change now is rapid and so natural but the change now is rapid and so natural systems will find it hard to changesystems will find it hard to change

Why is global warming occurring?Why is global warming occurring?

This is due to greenhouse gases which This is due to greenhouse gases which are vital for the planet. Without them out are vital for the planet. Without them out temperature would be 30C lower.temperature would be 30C lower.

But recently the amount of emissions have But recently the amount of emissions have increased.increased.

Particularly Particularly COCO22 , ,

A doubling of COA doubling of CO22 would cause a 7 C rise would cause a 7 C rise in temperatures in the higher latitidesin temperatures in the higher latitides

Effects of global warmingEffects of global warming

Rising sea levelsRising sea levels this would cause huge this would cause huge problems for low lying countries such as problems for low lying countries such as the Netherlands, many Pacific and Indian the Netherlands, many Pacific and Indian Ocean islands, as well as coastal citiesOcean islands, as well as coastal cities

Climate changeClimate change world wideworld wide. This would . This would lead to numerous global disasters.lead to numerous global disasters.

The number of floods, droughts and The number of floods, droughts and storms would increasestorms would increase

Solutions?Solutions?

The Kyoto Protocol was brought into effect in The Kyoto Protocol was brought into effect in February 2005February 2005

But the USA has not signed upBut the USA has not signed up

If a country went over its carbon limit then it If a country went over its carbon limit then it could buy Carbon credits from less polluting could buy Carbon credits from less polluting countries. If this does not work then fines could countries. If this does not work then fines could introduced, the country would be encouraged to introduced, the country would be encouraged to look for alternative.look for alternative.

Climate change levyClimate change levy