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Climate Change

  • Evidence for Climate Change
  • Natural and Human causes of Climate Change
  • Greenhouse Effect
  • National (UK) and International (Global) Effects of Climate Change
  • Living with Climate Change
  • Threats to Antarctica

What is Climate Change? 

Climate change is not the same as weather. Climate change is the change in average weather conditions of a place over a long period of time, usually 30 years. Weather is the day to day changes in atmospheric conditions.

What do people believe about climate change?

"Climate change is our greatest threat in a thousand years. If we do not take action, the collapse of our civilisations and the extinction of much of the natural world is on the horizon. We need to listen to scientists."

David Attenborough

Broadcaster

"The Earth is a dynamic system. Changes in climate, sea level and ice are normal. Climate is driven by the sun, Earth’s orbit, plate tectonics and the oceans. The atmosphere and life respond. Human have thrived in warm times and struggled in cool times. Humans cannot change climate."

Ian Plimer

Professor of Earth Sciences

"If our ecosystems collapse, so will our economy. We need to reverse climate change."

Leonardo DiCaprio

Actor

"To young people all over the world, we need to recognise our responsibility to take control of our future. The fate of our beautiful planet and our way of life is at stake."

Ellie Goulding

Singer and songwriter

What is the evidence for climate change?

There is plenty of evidence for climate change, from retreating glaciers, thinning of ice to changes in agriculture patterns. 

  • Over the last 100 years, global temperature has increased by 0.8⁰C.
  • Arctic ice has thinned by 65% since 1975.
  • Over the last 100 years, sea level has increased by 10-20cm.
  • Atmospheric CO2 is 40% higher now, than it was before the industrial revolution.

How does earth warm naturally?

What are the natural causes of climate change?

  • Volcanic eruptions – the ash from the volcano can travel around the world. This blocks out sunlight and causes global cooling (making temperatures drop). After Mount Pinatubo erupted in 2001, there was a 0.6⁰C drop in global temperature.
  • Solar output – these are black spots on the sun. When sunspot activity is at a maximum, it gets hotter. When it is at a minimum it gets colder.
  • Orbital change – the Milankovitch cycles. The Earth may become closer to the sun (interglacial period) and further from the sun (glacial period) every 100 000 years.

What is the enhanced greenhouse effect?

          Natural greenhouse effect (left side)               Enhanced greenhouse effect (right side)

The enhanced greenhouse effect shows how humans induce climate change by making the layer of greenhouse gases in the atmosphere thicker, therefore absorbing more heat.

What are the human causes of climate change?

  • Overpopulation – this is where the earth's population exceeds the available resources. It may lead to an increase in fossil fuels being extracted and burnt as well as an increase in deforestation and agriculture to increase food supply.
  • Burning of fossil fuels – this happens through producing electricity, fuelling vehicles and manufacturing. It emits greenhouse gases such as carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). These gases absorb heat, causing earth to warm up.
  • Deforestation – trees are carbon sinks (they remove CO2 from the atmosphere), the more we remove, the more CO2 in the atmosphere. Therefore, the layer of greenhouse gases remains thick.
  • Agriculture – land is cleared (deforestation) to make space for grazing cattle. Over 60% of deforestation in the Amazon Rainforest, Brazil happens so cattle can graze. This increases food supply.

What are the global effects of climate change?

  • Floods and Drought – as temperatures increase, flooding and drought will become more frequent. Mali, West Africa experienced their worst rains in 50 year during 2018, this washed away their entire crop leading to food shortages. Mali is lurching between droughts and floods.
  • Food Shortages - by 2050, Asia will suffer from food shortages as they struggle to grow rice due to a change in climate.
  • Migration of Species - species migrating for survival will cause change within ecosystems. Krill are moving south of the Arctic. This is a problem as Krill is a part of the diet of whales, polar bears and seals. It will cause food shortages for these species.
  • Change in Agriculture Patterns - where food struggles to grow in some place, it may prosper in others. South Korea had a very successful year for growing bananas during 2018. This is not typical of South Korea's climate.
  • Melting Ice - this is an effect of a warming world, especially in the Arctic and Antarctic. The Arctic ice has thinned by 65% since 1975.
  • Sea Level Rise - oceans rise due to melting ice. Coastal and are areas of low lying land will be most at risk from this. Sea levels have increased between 10 and 20cm over the last 100 years.
  • Global temperature increase - as the layer of greenhouse gases becomes thicker, more heat is absorbed. By 2100, global temperatures could increase up to 4⁰C.

How can we mitigate climate change?

Mitigation means to reduce the severity or seriousness of something, in this case the causes of climate change. We cannot stop the natural causes of climate change, but we can mitigate the human causes.

  • Alternative energy – using renewable energy such as solar, wind, tidal, HEP and geothermal reduces the reliance on fossil fuels and do not emit greenhouse gases. The UK gets 20% of its electricity from renewable energy and aims to increase this to 30% by 2020.
  • Afforestation (planting trees) – planting trees increases the amount of carbon sinks that remove CO2 from the atmosphere, which means less greenhouse gases. The UK has invested £24.9 million on a project to reduce deforestation and increase afforestation in the Amazon Rainforest, Brazil.
  • International Agreements – climate change is a global issue and many countries come together to agree on targets to reduce the causes and effects of climate change. In 2014, 194 countries signed the Paris Agreement. The aim is keep temperature increase below 2⁰C, increase carbon sinks and for developed countries to support undeveloped countries. However, there is no consequence for not keeping to the agreement. It is not law.

How can we adapt to climate change?

Adaptation means changing in order to live with an specific environment.

  • Change in Agriculture Patterns – climate change will have a huge impact on agricultural patterns as patterns of rainfall and temperature changes. We can adapt to this by creating irrigation systems where rainfall is low, growing crops in different locations or changing what we grow. However, this is difficult for poor farmers.
  • Managing Water Supply – climate change will create water shortages as a result of drought. We can manage water supply by reducing how much we use, the two button toilet flush is a good example. Pressing half-flush uses less water. We can also increase water transfer schemes. 
  • Reducing the Risk of Rising Sea Levels – By 2100 sea levels are expected to rise by a further 26–82cm. This will flood important agricultural land in countries such as Bangladesh and India as well as areas of low land such as the Maldives. The Maldives have built a 3m sea wall to stop sea level claiming the land as well as starting to build houses on stilts.

How will climate change impact Antarctica?

Climate change is the greatest long-term threat to Antarctica (amongst other threats such as overfishing, tourism, pollution and the exploration and extraction of oil and gas). Antarctica is larger than the United States of America and India combined. If the Antarctic ice sheet melted, sea level would rise by 60m. This is a problem for those species who rely on the ice for survival. 

Questions

1) How is climate change different to weather?

2) What are the natural and human causes of climate change?

3) How do we know climate change is happening?

4) What should governments do to mitigate and adapt to climate change?

5) What are the global effects of climate change?

6) How can trees cause and slow down climate change?

7) What does the UK do to act on climate change?