Climatic effects on species- range and behaviour

Every species has particular optimum environmental conditions for survival. As climate alters they either:

• Migrate (invading a new area and mixing with formerly non-overlapping species. This can lead to knock-on effects throughout the ecosystem and can cause extinctions)
• Adapt their behaviour

Changes in species distribution- Spatial

• Killer whales with tall dorsal fin are moving into previosuly ice-bound Artic waters and siplacing bowhead whales
• Adelie penguin rookeries being replaced by Gentoo penguins on the Antartic peninsulars
• 60 species of butterfly have moved north in Europe, e.g. Polygonia comma butterfly is spreading north in UK at a rate of 10km a year
• Concern that pests of species are linked with diseases could spread more widely, e.g. Anopheles mosquito which carries Malaria

Changes in species physiology and behaviour- Tempral

• Shifts in Phenology (timing of biological activities that take place seasonally)- migrant birds, butterflies and plants are arriving earlier.

Changes in physiology and behaviour- Tempral

• Polar bears find it difficult to hunt seals during the summer ice-free periods. As the Artic warms the Polar bears have become underweight as they have a shorter amount of time toi hunt for food.

What are the issues resulting from Climate Change??

Changing climates, shifting climatic belts and the effects on biomes

1. A change in that climate will therefore change that ecosystem
2. 'Macro-scale' effects

• Climatic ranges are moving North 50km-80km every 10 years
• Shifting climatic belts polewards (also known as the migration of climatic belts)

3. Shifting Climatic belts leads to changing biomes

• By 2100, 40% of biomes will have switched to a different state

Temperate Grasslands-Mid Latitudes

• Temperate Grasslands on the steppes of North Asia and North American prairies will have drier summers and colder winters.
• These regions are the 'bread baskets' of the world-the principle grain-growing areas
• Climate change will reduce grain yields,food production and income for farmers
• This could lead to food shortages

Tundra and Northern tree line-High Latitudes

• Melting permafrost leads to: Loss of habitats-wildlife adapted to survive tundra conditions, subsidence-damaging settlements,transport and oil pipelines in Alaska and Siberia, increased sediment in rivers- increased erosion of the banks affect wildlife including the salmon that migrate upstream to spawn.
• Release of methane and carbon dioxide previously locked up in frozen ground (positive feedback loop accelerating global warming)

Rainforest, Savanna and Desert-Low Latitudes

• Tropical biomes seem to be tied to specific climate tipping points (Gilf Kebir). When certain climatic thresholds are crossed (especially precipitation level/distribution), the one ecosystem can suddenly switch to another
• Could be beneficial to some areas-e.g. Sahel where movement of the rain belt Northwards could halt desertification

Increasing levels of Extreme Weather

Extreme weather events classified as hydro-meteorological hazards by the Emergency Events Database.

Increase in reported extreme weather

• Frequency (how often)
• Magnitude (size)
• Impact (amount of damage)

Flood events

• Coastal river and flash flooding
• 10% of land surface is very flood prone
• Flood prone land contains 40% of the world's people.
• Areas include Midwest USA, coastal South America, Bangladesh and Northern England.

Storms

• Mainly tropical cyclones (hurricanes, typhoons)
• Can include tornadoes and temperate storms
• Concentrated in tropical belts, especially coastal areas covering 7% of the world's area but 24% of the world's population.

Droughts

• A drought is when there is less than 50% median rainfall over 3 or more months
• Often includes extreme,heat,wildfires and the secondary hazard of famine
• Affects 40% of the world's land surface containing 70% of the population and 70% of agricultural production

Slides

• Can be a secondary hazard resulting from extreme weather (e.g. heavy rain or snowfall. Includes avalanches)
• Affects 5% of the world's population

What are the reasons for the increasing level of extreme weather?

• More reporting because of improved communication
• Different methods of recording events
• Population growth leads top densely populated hazard prone areas
• Deforestation and land degradation, increasing magnitude of floods and droughts
• Climate Change has an impact on extreme weather but there are other contributing factors

Risky Sea Levels

The IPCC (Intergovernment Panel for Climate Change) predicted the sea level rise for 2080

• Low Emission Scenario-9.48cm
• High Emission Scenario-16.69cm

Whatever happens sea levels will rise.

Causes (Key factors associated with climate change):

• Warming ocean-water expands and more precipitation (Thermal expansion).
• Exchange of water stored on land as glaciers and ice caps with ocean water.
• Sea levels could rise up by 7 metres if Greenland melted entirely.
• Glacial retreat

Impacts:

• The weight of ice cover caused crust to sink-creating a see-saw effect
• Out of the 15 largest cities-13 of them will be affected by sea level rise as they are on the coast
• Sea level rise in the UK will affect the South and East of the UK which would cause flooding and coastal erosion
• Small islands in the Pacific and Indian Oceans will be affected the most

Geometry of the Oceans

The oceans influence climate over long and short time scales. The oceans and the atmosphere are tightly linked together to form the most dynamic component of the climate system. The oceans play a critical role in storing heat and carbon. The ocean's waters are being constantly moved by powerful currents which are mainly wind-driven. These currents influence the climate by transporting heat. Currents involved in 'deep-water formation' are particularly important for climate. Apparently a small change in just one aspect of the ocean's behaviour can produce major climate variations over large areas of the Earth.

Thermohaline Circulation

What is it?

Thermohaline circulation is a part of the large-scale ocean circulation that is driven by global density gradients created by heat and fresh water fluxes. It is also known as the ocean conveyor belt, great ocean conveyor or the global conveyor belt. It supplies heat to the polar regions and regulates the amount of ice in those regions.

In 2005, the net flow of the Northern Gulf Stream had decreased by 30% since 1957.

Thermo-Heat
Haline-Salt Content

ENSO

El Nino

• Short-term climatic disruption
• Occurs at intervals between 2-7 years
• Typically lasts between 12-18 months
• Also known as ENSO warm event
• Arrival of warm surface water in the Eastern equatorial Pacific (off Peru and Equador)
• Often occurs at Christmas, giving name to event 'Christ Child'
• The current that brings cold water to the west coast of South America is called the Humbololts Current

Normal Air Circulation in the Central Pacific is called the Walker Loop

Process of a normal year of the El Nino Southern Oscillation

1. South East Trade Winds

• Part of global atmospheric circulation pattern.
• Not below -30 degrees and not above the equator.

2.Warm water builds up in Western Pacific

• Sea level is 50cm higher here.

3.Warm water heats the air causing convection currents and low pressure leading to high precipitation.

4.Tropical rainforest biome forms because of warm wet conditions

5.Cooler air sinks leading to dry conditions on the west coast of South America once the air has returned east.

Process of an El Nino year of the El Nino Southern Oscillation

1.South East trade winds drop

2.Warm water moves back towards the East

• Sea level on the Peruvian coast rises by 30cm

3.Air circulation reversed. Sinking air brings drought conditions to Western Pacific regions. Rising air causes convectional rainfall which can lead to floods in coastal areas of South America, which devastates the fishing industry.