global climate change (GCC)

greenhouse gases, effects, monitoring & predicting, control

why is the greenhouse effect needed?

Without the greenhouse effect the Earth would have a mean temperature of -15^oC and not 15^oC, which would be too cold for life to exist

how do greenhouse gases heat the atmosphere

in the atmosphere they absorb about 25% of the outgoing long wave energy (IR) and convert it into heat

7 types of green house gases

• Water vapour (H₂O)

• Carbon dioxide (CO₂)

• Methane (CH₄)

• Nitrous Oxide (NO_X)

• CFCs

• Tropospheric Ozone (O₃)

• Carbon monoxide (CO)

sources of CO2

Combustion of fossil fuels & deforestation

sources of CFCs

Aerosol propellants, refrigerants, fire extinguishers, foam plastics

sources of (NO_x)

Reaction of atmospheric O₂ & N₂ at high temperatures in engines & furnaces

sources of CH4

Livestock (anaerobic digestion uses bacteria in their stomach), landfill, paddy fields (both anaerobic decomposition) & leaks from gas fields

sources of O3

Reaction of NO₂ produced from car engines with uv

ways to reduce CO2 levels

1. Use renewable energy sources
2. Afforestation
3. Carbon sequestering

Ways to reduce methane levels

1. Eat less beef and pork
2. Eat more organic food produce
3. Advanced approaches to oil and gas leak detection

Ways to reduce nitrogen oxides levels

Use low nitrogen fuels.

Ways to reduce CFC levels

1. Buy air-conditioning and refrigeration equipment that do not use HCFCs as refrigerant.
2. Buy aerosol products that do not use HCFCs or CFCs as propellants

Ways to reduce tropospheric ozone levels

1. Vapor recovery nozzles at the gasoline pumps to reduce refueling emissions.
2. Cleaner burning gasoline reformulated to reduce VOC, NOx and other pollutants.
3. Strict NOx emission limits for power plants and industrial combustion sources.

what are the 3 main changes GCC cause

• in the oceans

• in the cryosphere

• in climate processes

what changes does GCC cause in the oceans

• wind and current patterns

• thermohaline circulation in the North Atlantic

• sea level rise

two reasons sea levels rise

1. Melting glaciers and land ice sheets add water to the ocean

2. Thermal expansion - when water is heated it expands

thermohaline circulation in the North Atlantic

Rising temperatures begin to melt ice from Greenland's icecap. Fresh water from the ice caps are less dense than sea water, this dilutes the sea water (as salinity levels are changed). The sea water will then become less dense than normal, this will sink less, slowing the oceans currents

• wind and current patterns

During normal conditions in the Pacific ocean, trade winds blow west along the equator, taking warm water from South America towards Asia. To replace that warm water, cold water rises from the depths — a process called upwelling.

During El Niño, trade winds weaken. Warm water is pushed back east, toward the west coast of the Americas.

effects of El Nino

strong effect on marine life off the Pacific coast. During normal conditions, upwelling brings water from the depths to the surface; this water is cold and nutrient rich. During El Niño, upwelling weakens or stops altogether. Without the nutrients from the deep, there are fewer phytoplankton off the coast. This affects fish that eat phytoplankton and, in turn, affects everything that eats fish. The warmer waters can also bring tropical species, like yellowtail and albacore tuna, into areas that are normally too col

what does GCC affect in the Cryosphere

• snow cover

• Glaciers 

• Ice shelves

• Ice sheets and land ice

• Sea ice

how is snow cover affected by GCC

Reduced – amount and duration

how are glaciers affected by GCC

changes in extent and speed of movement

how are ice sheets and land ice affected by GCC

changes in thickness and movements.

how are ice shelves affected by GCC

changes in the break-up of ice shelves and the impact on land ice movements

how is sea ice affected by GCC

changes in thickness and area of sea ice cover.

what is the albedo effect

• Albedo is the fraction of solar energy (shortwave radiation) reflected from the Earth back into space

• Surface that are white are more reflective

• Therefore, the smaller the cryosphere, the less energy is reflected, warming the planet

how has GCC affected climate processes

• precipitation changes

• wind pattern changes

how has precipitation changed from GCC

• amount, duration, timing and location

• changes in proportions of rain and snow.

how has wind patterns changed from GCC

• direction

• velocity

ecological effects of GCC

• hibernation

• photosynthesis

• synchronicity

• parasites and disease

• species distributions

how is hibernation affected

• hibernating species may benefit from being able to feed for more of the year

• or may suffer, as by being disturbed more frequently,

or when food is unavailable

• wetland species - depending on their location, changes in precipitation will cause wetlands to grow or shrink

how is photosynthesis affected

• As temperatures increase, the rate of photosynthesis also increase

• The rate of growth in plants (and single celled organisms) increases

• More plant biomass

• More potential food for herbivores

• But also an increase in toxins

how is synchronicity affected

• Species are often ‘interdependent’ 

• Climate change may lead to changes in the timings of ecological events

• The survival interdependent species may be reduced

how are parasites and diseases affected

• Warmer and wetter climates often help spread parasites and disease

• Increase in the range and breeding sites of vectors (often mosquitos)

• Increased cases of malaria, rift valley fever and many other (non-human) examples

how are species distributions affected

• Species are adapted to their habitats 

• Species have a range of tolerances

• Changes in abiotic and biotic factors cause a change in species distribution

• Climate is changing rapidly, adaptation and evolution are often too slow

• Suitable new areas may not be available (mountains, coasts, poles)

• Human land use may block movement (roads)

What makes a species most vulnerable to extinction by climate change

• Small ranges

• High latitudes 

• High elevations

• Specialist species

• Slow migrators/colonisers 

• Island species

what are the limitations in the available data

• Limited Historical Data - Some historic data cannot be trusted

• indirect sources (proxy data)

• incomplete understanding

Uncertainty of ecological impacts of climate change

• changes in species survival caused by changes in abiotic factors

• changes in species survival caused by changes in biotic factors

• changes in species distribution

• population fragmentation.

data collections

• Satellites

• argo floats

• buoys

positive feedback

A situation where an initial change causes a reaction that increases the original change

positive feedback mechanism pt 1

Increased temperatures

Increased levels of atmospheric methane

Increased rate of anaerobic decomposition

positive feedback mechanism pt 2

Increased temperatures

Decreased snow and ice

Decreased albedo

More longwave radiation emitted by Earth

More shortwave radiation absorbed by Earth’s surface

negative feedback

A situation where an initial change causes a reaction that reduces the original change

negative feedback mechanism

Increased temperatures

Increased rate of photosynthesis

Decreased levels of atmospheric carbon dioxide

Negative feedback (temperature returns to normal)

Control of Global Climate Change

• legislation

• behaviour

• tech

legislation examples for controlling GCC

• kyoto

• paris 2015 - aims to limit global warming to less than 1.5°C compared to pre-industrial levels

tech examples for controlling GCC

• Catalytic converters 

• Energy Conservation