Climate change

What is climate?

• Climate is not the same as weather

• Weather is more short term – it is the temperature, cloudiness, humidity, etc. at a given time, based on what happens each day in our atmosphere

• Climate also includes:

• Seasons

• Weather extremes (hurricanes, droughts, floods, etc.)

• Climate is the average pattern of weather for a particular region over time

What is climate?

• Earth is a system in which the land, water and atmosphere all work together to create the particular climate of a region

• Variations in any of the components of the Earth’s system will result in different climates – this is why deserts are so different to wetlands!

• Two of the most important factors determining an area's climate are air temperature and precipitation

http://www.metoffice.gov.uk

Climate types

Greenhouse effect

• Heat from the sun warms the surface of the Earth

• Some of this heat is absorbed by the Earth, and some is radiated back out towards the atmosphere

• Naturally occurring gases in the atmosphere, known as greenhouse gases, act like an insulating layer and absorb much of this heat

• Some of this absorbed heat is then re-radiated back towards Earth

• This process is called the greenhouse effect, as the gases act in a similar way to the glass of a greenhouse

Without it, the Earth would be extremely cold!

Greenhouse gases

• There are several different gases in the atmosphere which are responsible for the greenhouse effect – these are called greenhouse gases

• Can you name any greenhouse gases?

Carbon dioxide

Methane

Water vapour

OzoneNitrous oxide

Chlorofluorocarbons (CFCs)

• These gases occur naturally in the atmosphere

An increase in greenhouse gases

• Human activity is increasing the concentration of these naturally occurring greenhouse gases in the atmosphere

• One of the consequences of this imbalance is global warming

• This disrupts the natural balance of the system, causing changes in Earth’s climate

Global warming

• An overall increase in the Earth’s surface temperature – the Earth’s temperature has risen by about 0.75oC globally

• Using climate change models, some scientists have predicted that the Earth’s average temperature will increase by 3 to 5oC over the next 100 years

• This long-term increase in the Earth’s surface temperature is referred to as ‘global warming’

• However, global warming is not the only consequence of an increase in greenhouse gases – because there are many effects, the term ‘climate change’ is often used

What is climate change?

Climate change is a long-term change in the Earth’s climate or in that of a region on Earth

Can you name any other effects of climate change?

While climate change is a natural process, this term now usually refers to the relatively rapid changes caused by human activities

• Climate change includes global warming, but also includes everything else that an increase in greenhouse gas concentrations will affect

RECAP:

• Global warming refers to surface temperature increases

Other consequences of climate change

• Warming oceans – they absorb 80 percent of the heat

• Rising sea levels – sea levels have risen by about 17 centimetres globally

• Ocean acidification – more carbon dioxide from the atmosphere is being absorbed into the ocean, making the water more acidic

Other consequences of climate change

• Declining Arctic sea ice - the Arctic sea ice has been declining since the late 1970s

• Shrinking ice sheets - In Greenland and the Antarctic, ice sheets have started to shrink

• Extreme weather - In the last decade there were three times more weather-related natural catastrophes

Causes of climate change

• Scientists agree that the main cause of climate change is human activity, which increases the levels of greenhouse gases in the atmosphere, magnifying the ‘greenhouse effect’

Greenhouse gases – which are the main contributors?

• Human activity is increasing the level of several different greenhouse gases. How much each of these gases affects climate change depends on three factors:

- How much is being produced

- How long the gas stays in the atmosphere

- How powerful the gas is at trapping heat

Carbon dioxide

• The main source of carbon dioxide is the burning of fossil fuels

• Fossil fuels are used to:

- Drive cars

- Provide electricity

- Heat our homes with oil or gas

Deforestation - Plants remove carbon dioxide from the atmosphere by photosynthesis – a process where plants use carbon dioxide and sunlight to produce energy

- If trees are cut down, the amount of carbon dioxide being removed from the atmosphere is reduced

Methane• Methane is produced naturally:

– By living animals, such as cows!– In areas of waterlogged soil– By rotting plants and other organic material

• However, human activities are increasing the levels of methane being released into the atmosphere in several ways:- Industry – methane is produced during the production, processing, storage and distribution of natural gas - Increase in cattle rearing – cows naturally produce methane, but an increase in cattle rearing for milk and beef has increased the amount of methane- Rice paddies – rice is grown in flooded land known as rice paddies. There has been an increase in the number of rice paddies due to an increasing population, which has led to higher levels of methane being released- Landfills – as waste decomposes in landfills, methane is produced

Effects of climate change on animals and plants

• Scientists predict that man-made climate change could contribute to a mass extinction of wildlife in the near future

• Climate change affects many species of animals and plants from a range of different habitats and climate types

• Many plants and animals have specific habitat requirements and need certain climate conditions to survive, and these are being altered by climate change

Melting polar ice caps, increasing acidification of the ocean, and loss of land due to rising sea levels are just a few examples of how climate change is affecting species and their habitats

Case study 1 - Polar bear

• Individuals are having to travel longer distances across open water – this uses up vital energy reserves

• Climate change is the biggest threat to polar bears

• Dependent on sea ice for survival • Need ice as a platform to hunt seals and to breed

Case Study 2 - Clownfish and anemones

• Clownfish depend upon sea anemones for protection from predators

• Sea anemones are under threat as they are normally found on coral reefs, which are globally declining due to climate change

• A loss in sea anemones will lead to a decrease in clownfish populations

Case Study 3 - Ruby-throated hummingbird

• Migratory birds rely on environmental signs to let them know when it is time to migrate

• Ruby-throated hummingbirds winter in Central America, and then migrate hundreds of kilometres to breed in North America

• Research has shown that changing climate in the wintering grounds is causing the hummingbirds to start their migration to North America up to 18 days early

• This could mean arriving in the breeding areas before food and nesting material is available, or before the temperatures are suitable for survival

ActivityClimate change is affecting species both directly and indirectly.

We are now going to play a game to learn about the different ways in which species are being affected by climate change.

1. Read the factsheet about how ten different species are affected by climate change.

2. Mix the cards up and place them face-down in a grid of four cards by five cards.

3. Take it in turns to turn over two cards and see if they match – you must match a text card with the relevant picture card.

4. If they match, you keep the cards and get another go. If they don’t, turn the cards back over, keeping them in the same place. It is then your opponent’s turn.

5. The winner is the person who collects the most cards.

How you can help!

There are many things you can do to help:• Walk or cycle more• Turn lights and other electric devices off• Reduce, Reuse, Recycle• Eat less meat• Spread the word!

Summary

• Climate change is a long-term change in the Earth’s climate or in that of a region on Earth, but now usually refers to changes caused by human activities

• Humans are adding more greenhouse gases to the atmosphere which is amplifying the greenhouse effect

• Some species are more affected by climate change than others

• There are things you can do to help reduce the effects of climate change!