Models of Global Warming

Using Computer Models…

• Take years to develop• Difficult to get them to account for all

factors• Unreliable• Possible to build models that are

biased in either direction• Models have limitations

Risk of Flooding• Melting at the polar

ice caps increases sea levels across the Earth (and affects animals that live there!)

• Coastal regions are in danger of being lost under the sea

• This could affect hundreds of millions of people worldwide

• As the Earth warms up sea levels rise due to expansion

The Maldives

• Current estimates put the rise in sea level at 0.9cm per year

• 80% of its 1200 islands are no more than 1m above sea level

• Could be lost within 100 years

• Oct 2009 – President holds underwater cabinet meeting to raise awareness

The Effect on Organisms

• Affects enzymes• All organisms will

have optimum temperatures at which their enzymes function

• Global warming may increase or decrease rate of reactions within living things

Organisms in the Tropics…

• Majority of species are found in the Tropics

• Climate in Tropics fairly constant

• Little tolerance for change

• Temperature changes of even two degrees could be fatal to some species

• Insects are particularly vulnerable

Effects on Reproduction…• Breeding in many

organisms is in response to a change in temperature or day length

• Longer, warmer days mean more favourable conditions for raising offspring and mean greater survival chances

• As the Earth warms, the onset of reproduction in many species, both plant and animal, will be earlier

Great for some species, not so for others…

• Hedgehogs can have more than one litter of babies each year

• The longer and warmer the spring/summer ,the more litters they are likely to raise

BUT…• The young hedgehogs have

to gain enough weight before the onset of autumn if they are to survive hibernation through the winter

• If they don’t gain enough weight, they don’t hibernate and may starve to death

Crocodile Reproduction• Nests built on land, well

above water level• Constructed from grasses,

organic matter, mud and soil

• Close to water• Lay 13-20 eggs at a time• Nests guarded ferociously• Temperature very

important• 32-33OC; all embryos will

be male• Cooler or warmer; females

develop

• More breeding cycles can increase the numbers of individuals in a population

• However, if the breeding cycles of their prey also change, and they can’t adapt it can lead to a decrease in overall population numbers

Changes in species distribution

• Global warming could affect the range of many species

• Animals able to survive change more easily

• May affect spread of disease as well

• Insect-borne diseases• Insects not previously found in

Britain are becoming more common

• Possibility that malaria may become prevalent in Europe and Britain by 2100

• Sunfish seen off coast of NE Scotland in 2009! Usually found in temperate and tropical waters

• They need to be in water warmer than 12oC – any cooler than this and they can die