Global Climate Change: Environmental Consequences

Global climatic change:

environmental consequences

Global temperature

variations and

heatwavesRising sea

levels

Melting of ice caps and glaciers

Thawing peat bogs

El ninoGrowth of tropical belt

Changing patterns of

rainfall

Declining crop yields

Impact on wildlife

1. Global temperature variations and heatwaves

Here’s an article from the newspaper about a heatwave in the UK in the summer of 2009:

http://www.guardian.co.uk/uk/2009/jul/01/heatwave-met-office-health-advice/print

Abnormally hot periods of time

Will be felt most in urban areas (urban heat island)

Rising possibility of heatwaves

Sea and ocean temperatures

rise

Molecules near the surface

move further apart

Water volume increases Sea levels rise

2. Rising sea levelsCaused by TWO factors:

1 – Melting of ice sheets and glaciers2 – Thermal expansion

THERMAL EXPANSION – as sea and ocean temperatures increase, the water molecules near the surface move further apart, so the water volume increases and the sea level rises

Melting of ice caps and glaciers

Melting of ice caps and glaciers

Climatologists are concerned that melting Arctic ice could disrupt the Gulf Stream which could result in temperatures in western Europe falling by at least 5C.

Melting of ice caps and glaciers• Antarctic has

two main regions (West and East)

• Both covered by ice (average 200m thick)

• East = stable as ice is mainly on land

• West = less stable as much of the ice base is under water

• In 2007 the sea ice around Antarctica melted back to a record low

Melting of ice caps and glaciers

• Since 2007 – the movement of glaciers towards the sea has speeded up.

• There are now concerns about the long-term stability of Antarctica’s two main ice shelves – Ross ice shelf and the Flichner ice shelf

• Greenland and Antarctica are the worlds two major ice masses. It has been predicated that total melting of these would result in a 70m rise in sea level (not predicted at present)

Thawing peat bogsA peat bog is - (wet spongy ground of decomposing vegetation; has poorer drainage than a swamp; soil is unfit for cultivation but can be cut and dried and used for fuel)

• Siberia – melting permafrost (permanently frozen ground) is starting to thaw for the first time since the end of the last ice age (11,000 yrs ago).

• This is the worlds largest frozen peat bog.• Scientists worry that if it thaws it will release

billions of tonnes of METHANE – a green house as 20 times more potent than CO2 into the atmosphere.

El Nino

This is complicated – we’ll do this next

lesson!

Growth of the tropical belt

…is expanding further north and south. Poleward movement of subtropical dry belts could affect agriculture and water supplies in the Mediterranean, South-west USA, northern Mexico, southern Australia, southern Africa and parts of Latin America

Changing patterns of rainfallWet areas will get wetter…..dry areas drier…

Declining crop yields • Higher temperatures have already had an impact on global yields of wheat,

corn and barley. • Crop yields fall by 3-5% for every .5C increase in average temperature. • This could lead to food shortages• This could lead to conflict.

Impact on wildlife• Many species of wildlife will go extinct as they can’t adapt to new conditions

quickly enough• Arctic species e.g. the polar bear will be effected

How many of the 9 consequences mentioned

in this power point can you remember?

List them – don’t cheat!