Zusammenfassung der Ressource
Climate
Change
- Past climate
change.
- Some natural causes of climate
change.
- Earth's orbit changes a small
amount once every 100000 years
(Milankovitch cycles).
- Amount of energy from the Sun changes
over an 11-year cycle.
- Volcanic eruptions put ash
dust into the atmosphere
causing a cooling effect.
- Large asteroid collisions
can cause cooling as
material blocks out the
Sun. Asteroids hitting the
Earth can cause huge fires
which release massive
amounts of carbon dioxide
which has a warming
effect.
- Ocean current changes can cause
cooling and warming (e.g. UK, warm
and wet climate because of warm
Atlantic currents. Current can
sometimes shift so there is a cooler
climate for a short period of time.
- The impact of climate
change.
- Case study: The Little Ice
Age.
- A colder period in
Northern Europe
starting in the 15th
century and lasting
the mid 19th
century.
- Crops did not grow
well which meant less
productivity and less
food for people.
- The winters were very
cold and the summers
were short.
- Causes: Could be
caused by... fewer
sunspots or volcanic
ash in the
atmosphere. Unlikely
to be caused by...
humans because not
enough industry to
cause climate
change.
- Evidence: Diaries,
newspapers and
paintings and the tree
rings in the old trees
are thinner during cold
years.
- The impact of climate change on
megafauna.
- Megafauna such as mammoths,
giant beavers and sabre-toothed
tigers, had evolved during the Ice
Age.
- The Ice Age ended and
temperatures rose 5°C in 10000
years.
- The megafauna couldn't adapt to the
warmer climate and became extinct.
Hunting by early humans could also
have been a factor in their extinction.
- Present and future climate
change.
- Pollution.
- 1. Carbon dioxide and
methane are greenhouse
gases linked to human
activity.
- 2. The rise in greenhouse gas
emissions matches the start
of the Industrial Revolution.
- 3. Current levels of carbon
dioxide are thought to be
at their highest for at least
650000 years.
- 4. Current levels of
methane are thought to be
at their highest for at least
900000 years.
- 5. Methane is 21 times
more potent than carbon
dioxide.
- Greenhouse
effect.
- 1. The Sun warms up the
Earth's surface.
- 2. Some warmth
radiates up from the
surface and into the
atmosphere.
- 3. Without greenhouse
gases the warmth escapes
back into space.
- 4. With the
greenhouse gases,
some warmth is
trapped, in the same
way the glass in a
greenhouse traps
warm air. We need
greenhouse gases -
Just not too many!
- Greenhouse
gases.
- As a country develops, the amount of greenhouse gases it
releases into the atmosphere is increased. More carbon
dioxide is produced because: there is more industry, e.g.
steel and cement making, more energy is needed so more
fossil fuels are burned, transport increases so more oil is
burned as petrol and diesel and land is needed so there is
deforestation (trees are often burned). More methane is
produced because there is more demand for meat so there
are more farm animals.
- Climate change
challenges.
- The UK
climate.
- Climate of the UK is mild (cool) and
wet. Described as temperature
maritime. Several factors impact om
the UK's climate. Latitude affects how
much Sun the UK gets and how strong
it is during the seasons. The North
Atlantic current (or drift) keeps the UK
warmer than other places of the
same latitude. Air masses bring
weather conditions with them from
where they originated. The UK is
affected by five air masses. The
prevailing winds are from the Atlantic
Ocean in the south west. They pick up
moisture from the sea and often bring
rain to the UK.
- UK climate
change.
- Possible changes to the UK's climate
include: average temperature rise.
Less predictable rainfall patterns with
drier summers. Changing seasons -
possible longer summers and more
extreme cold in winter. Changes will
happen because: the North Atlantic
current is likely to move which will
probably reduce sea temperatures
and bring less rainfall. More air
masses will come from the north,
bringing storms and perhaps more
extreme cold in winter. The paths of
depressions (which bring rain) may
be altered by these changes in air
masses and ocean currents.
- Predicting the effects of climate
change.
- In 2008 global
carbon dioxide
reached 380
ppm (parts per
million).
- If concentrations go
over 550 ppm,
predictions are that
global temperature rises
will be 6°C or more.
- Possible consequences:
Millions of people
would lose their homes
due to sea-level rises.
Changes to world
weather patterns would
cause droughts and
storms leading to
famines and disasters.
Animal and plant
species would not be
able to adapt fast
enough to the changes.
- If concentrations stay under
550 ppm, predictions are
that global temperature
rises will not go over 2°C.
- Possible consequences:
Sea level might rise by
1 m, causing coastal
flooding. More storms
and hurricanes. Some
species may become
extinct, others would
shift to new zones.
- Climate change in the
UK.
- Environmental
impacts.
- Sea level rise will lead to loss of coastal land and
increased erosion. Risk on low-lying cities flooding,
e.g. London. More severe storms and longer
summer droughts. Changes to fishing industries if
fish species move to different waters. Ecosystem
change could mean some plant and animal species
move into new areas and new (invasive) species
emerge. Warmer temperatures could encourage
diseases such as malaria.
- Economic
impacts.
- And increase in refugees from other countries hit
hard by climate change coming to the UK. Warmer
weather may mean farmers can grow different
crops and enjoy a longer growing season. Hotter
summers could mean more people have holidays in
the UK (so less air travel overseas). Damage to cities
such as London from flooding would be extremely
expensive and very disruptive. Cost of protecting
places from flooding will be expensive and in some
cases not practical. Housing design might need to
be altered so that less water is wasted and higher
temperatures are dealt with.
- Climate change in
Bangladesh.
- Environmental
impacts.
- River flooding (which is already severe)
would become worse from heavier rains
and sea level rise. Tropical storms could
become even more frequent and may
move further inland, doing more damage.
The dry season is already getting longer
and this could cause more droughts.
- Economic
impacts.
- A small rise in sea level (just a few cm) could massively reduce Bangladesh’s farmland and
agricultural output. More river flooding would mean more damage to people’s homes and more
disruption to lives and the economy. More intense tropical storms and storms spreading inland
would increase damage to homes, lives and infrastructure. Bangladesh has a large, fast growing
population; many are farmers who need land to work. The cost of protecting homes and
businesses from flooding is more than people or the government can afford. Coastal flooding
damages farmland by making the land too salty to grow crops. Shrimp farming is very important
but rising sea temperatures may damage this from the aquaculture. Increased flooding will
increase the spread of water-borne diseases.