Download What is climate change?

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 is the average pattern of weather for a particular
region over time
• Climate also includes:
• Seasons
• Weather extremes (hurricanes, droughts, floods, etc.)
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
• Two of the most important factors determining an area's climate are
air temperature and precipitation
• 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!
Climate types
http://www.metoffice.gov.uk
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
• These gases occur naturally in the atmosphere
• Can you name any greenhouse gases?
Chlorofluorocarbons (CFCs)
Carbon dioxide
Methane
Water vapour
Ozone
Nitrous oxide
An increase in greenhouse gases
• Human activity is increasing the concentration of these naturally
occurring greenhouse gases in the atmosphere
• This disrupts the natural balance of the system, causing changes
in Earth’s climate
• One of the consequences of this imbalance is global warming
Global warming
• An overall increase in the Earth’s surface temperature – the Earth’s
o
temperature has risen by about 0.75 C globally
• This long-term increase in the Earth’s surface temperature is
referred to as ‘global warming’
• Using climate change models, some scientists have predicted that
o
the Earth’s average temperature will increase by 3 to 5 C over the
next 100 years
• 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
 While climate change is a natural process, this term now usually
refers to the relatively rapid changes caused by human activities
RECAP:
• Global warming refers to surface temperature increases
• Climate change includes global warming, but also includes everything
else that an increase in greenhouse gas concentrations will affect
Can you name any other effects of climate change?
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
• 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
• Individuals are having to
travel longer distances across
open water – this uses up
vital energy reserves
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
Activity
Climate 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!