CLIMATE CHANGE GEOGRAPHY OCR B!!! WOOOO

climate change definition

large-scale, long-term changes in the average temperatures and weather patterns

Changes in climate from Quaternary period to now

• the last 2.6 million years are the Quaternary period, there have been 60 cold periods and warmer interglacial periods

• glacial periods last tentimes longer than interglacial, since the last glacial period, 150000 years ago the climate has been warming

• global warming is the term used to describe the rapid increase in global temperatures over the last century

• today our average temperature is higher than during almost all of the last 400,000 years

• since 1880 the average global temp has risen by 0.85 c, most since 1970

ice cores evidence for climate change

• trap ash, air bubbles and microbes

• the air bubbles contain CO2 providing information about past temperatures

• ice cores give information regarding the climate for the last 2.6 million years

preserved pollen evidence for climate change

• allowes scientists to know which plants were located where

• the climate requirements of those plants can then be used to know what the climate conditions were

historical sources - evidence of climate change

• diaries and art - such as painting of the Thames River frost fairs

• these are subjective and so may be inaccurate

tree rings - evidence of climate change

• each ring of the tree shows a year’s growth

• during warmer and wetter years trees grow more and so the rings are larger

• fossilised tree remains enable scientists to examine the climate over thousands of years

art and diaries - evidence of climate change

• paintings and diaries provide evidence seen by people during past colder and warmer periods

• paintings of the frost fairs on the river Thames in London in the 19th Centuy

• Diaries kept by people such a a gentleman farmer from North-West England dating back to 1815

natural greenhouse effect - essential to the survival of life on Earth

• Greenhouse gases in the atmosphere allow sort-wave radiation from the sun through to the Earth’s surface

• the greenhouse gases absorb some of the long-wave radiation (heat) and stp it from radiating out into space

• this maintain the Earth’s average temperature

• without the greenhouse effect the average temperature would be -18C

greenhouse gases from natural sources

water vapour - evaporation from the oceans/seas and plants

Carbon dioxide : volcanic eruptions, wildfires and respiration

methane : emitted form oceans and soils as part of decomposition, termites also emit methane

nitrous oxide: soils and oceans

Causes of Natural Climate Change - Milankovitch Cycles

• Long term changes to the Earth’s orbit and position

• changes how much solar radiation the Earth recieves

• Earth’s orbit changes evert 100,00 years

• more circular orbit = cooler periods

• elliptical orbit = warmer peirods

• The Earth’s tilt varies every 40,000 years and the greater the tilt the hotter summers are and colder the winters are

• every 24,000 years, Earth wobbles on its axis and can affect the seasonal temperatures

Causes of Natural Climate Change - volcanic eruptions

• large scale eruptions lead to vast quantities of ash being ejected into the atmosphere

• ash in the atmosphere block solar radiation leading to a decrease in temperatures

Causes of Natural Climate Change - sunspot acitvity

• sunspots = dark sports appearing on the sun’s surface

• increased activity = linked to higher average temperatures as they indivate that the sun’s effectiveness at radiating heat is increased

• the IPCC state the role of sunspots in climate change in minimal

Causes of Natural Climate Change - Atmoshperic dust

Asterioids and meteors entering the Earth’s atmosphere may increase the amount of dust, decreasing temperatures

enhanced greenhouse effect

• less long-wave radiation (heat) escapes the atmosphere

• short- wave radiation (heat) from the sun passes through the atmosphere

• more heat is absorbed by the greenhouse gases

• increase build up of greenhouse gases

• trapping long wave radiation from escaping the atmospere

Human Sources of Greenhouse Gases - Carbon Dioxide

• burning of fossil fuels, burning of wood,vehicles

Human Sources of Greenhouse Gases - Methane

• Decay of organic matter - manure, waste in landfil, crops

• released by cattle and during rice cultivation

Human Sources of Greenhouse Gases - Nitrous Oxide

• Artificial fertilisers

• burning fossil fuels

Human Sources of Greenhouse Gases - CFCs

• aerosols

• refrigeration units

• air conditioning

Human Sources of Greenhouse Gases - fossil fuels

• accounting for almost 50% of global greenhouse gas emissions, used in constructuion, heating, manufacturing, energy production

Human Sources of Greenhouse Gases - agriculture

• Deforestation to clear land for grazing and crops leads to less CO₂ being absorbed during photosynthesis

• The production of fertilisers and pesticides uses fossil fuels

• Increased raising of dairy and beef cattle as well as rice cultivation increases methane emissions

• Artificial fertilisers also increase the amount of nitrogen oxide released into the atmosphere

environmental impact of climate rise - sea level rise

• sea level has risen between 20-23cm since 1880

• rises 3.2 mm every year

• estimates 410 million people will be at risk by 2100

• thermal expansion - water expands when warm increasing the volume of water in seas and oceans

• melting glaciers - adds water to the seas and oceans

• melting ice sheets - ice in the Arctic and Antarctic is melting adding water to the seas and oceans

environmental impact of climate rise - sea level rice social environemntal economic impacts

social

• displacement of peope form their homes and communities

• food and water supplies threatened by salt intrusion

• food shortages lead to malnutrition and famine

environmental

• destruction of ecosystems including coral reefs and mangroves

• ocean acidification

• increased coastal erosion

• changing patterns of animal migration and behaviour

economic

• the cost of building flood defences

• relocation of people and building of new homes is expensive

• loss of jobs

• reduction in tourism due to the impact on coastal resorts

Maldives are more at risk

over 80% of its islands are less than 1m above sa level

forecast that if sea levels continue to rise the islands will be uninhabitable by 2050

government - constructuion of an artificial island HULMALE, ortheast of capital Male

Flood wells and defences constructed around islands

extreme weather events

• warmer ocean temp increase the amount of evaporation leading to more frequent and severe stroms

• droughts and heatwaves = more common due to increasing average global temp

• forcing poeple to move

• UN sttates than an annual average of 21.5 million people were displaced by weather-related events between 2008-16

• estimated suggest this could rise to a total of 1.2 billion poeple displaced by 205-

Social, Environmental and Economic Impacts of Sea Level Rise

social

• crop yields in sub - Saharan Africa are estinated to reduce by over 20%

• food shortages lead to malnutrition and famine

• lack of freshwater dur ot reduced precipitation

• spread of disease due to higher temp and flooding

environmental

• increased water temp in sea

• changing patterns of animal migration, hibernation and behaviour

• increased wildfires (drier conditions)

• reduced biodiversity due to loss of animal and plant species

economic

• decline in toursim in some areas

• ski resorts due to lack of snowfall

• extreme temperatures such as in Europe in 2023 deter people from warmer areas

weather patterns in the uk

• impacted by climate change

• ten warmest years on record in uk have occured in the last 20 years

• 6 of the ten wettest years in the last 25 years

• predicted by 2050 uk will have higher av temp in Se between 2.2.5 c higher

• days reaching over 40 predicted to be 10 times more likely

• wetter winters, particularly in east, over 20% in some areas

• drier summers, much of the uk experiencing a 20-20% decrease in precipitation

Social, Environmental and Economic Impacts of Changing Weather Patterns

social

• increased deaths due to extreme heat

• in 2022 te extremes in temp in Europe led to 61,000 excess death

• people with respiratory and heart condition will be really affected

• fewer deaths from cold

• hosepipe bans increase due to water shortages

environmental

• ecosystems may be affected yb drought, flooding and wildfires

• increase in wildfires due to direr conditions in summer

• changes in species in the Uk and the water around the uk due to higher temp

economic

• tourism may incr due to warmer, drier climate in summer

• growing seasons will be longer, increasing income for farmers and exports

• new types of crops can be introduced - citrus, fruits, olives

• less water available for irrigation and power stations