Climate Change

Discussion

Rapid climate change, caused by global warming, is threatening biodiversity, agriculture and human settlements.

Increasing temperatures in higher latitudes are causing glaciers and sea ice to melt faster in summer than they can rebuild in winter. Increased ocean temperatures in the lower latitudes are causing cyclone frequency and intensity to increase. Warming temperatures in general are causing species and ecosystems to either higher latitudes or higher altitudes.

The threat of climate change can be reduced by:

Adaptation can involve:

Readings

Global Warming

'No Doubt' Global Warming is Real. ABC, 2003.12.4

Global warming is real and is being caused by people, say Thomas Karl and Kevin Trenberth, two top US Government climate experts. Industrial emissions are a leading cause, not natural forces.

Carbon dioxide levels in the atmosphere have risen by 31 per cent since pre-industrial times. Carbon dioxide is the number one greenhouse gas, causing warming temperatures by trapping the Sun's energy in the atmosphere.

The likely result of global warming more frequent heat waves, droughts, extreme precipitation events, and related impacts, eg, bushfires, heat stress, vegetation changes, and sea-level rise.

Between 1990 and 2100, there is a 90 per cent probability that average global temperatures will rise by between 1.7 and 4.9 degrees Celsius because of human influences on climate.

Climate change is truly a global issue, one that may prove to be humanity's greatest challenge. It is very unlikely to be adequately addressed without greatly improved international cooperation and action.

Consequences of Global Warming

Global warming is real, and the consequences don't look good.

Case Closed: The Debate about Global Warming is Over. Gregg Easterbrook, Issues in Governance Studies, June 2006

While artificial climate change may have some beneficial effects, the odds are we're not going to like it.

Effects include:

The effects of global warming are upon us now.

The Climate Disaster is Upon Us Now. Michael McCarthy, The Independent, 2006.9.15

Global warming is causing record heatwaves, record hurricane seasons, and accelerating shrinkage of ice masses.

The European heat wave of 2003 which killed more than 30,000 people. The UK's record temperature topping 100F for the first time in that year. The record US hurricane seasons of 2004 and 2005, culminating in Katrina. The great ice masses now shrinking rapidly everywhere - almost every mountain glacier, the great Greenland ice sheet, the great ice sheets of Antarctica, the legendary African snow on the top of Mt Kilimanjaro, and the ice of the Arctic, whose rate of disappearance, we now learn, has increased explosively.

The world is changing in front of us.

From Alaska to Australia, the World is Changing in Front of Us. Daniel Howden, Andrew Buncombe, Justin Huggler, The Independent (UK), 2006.9.15

Accelerated climate change due to global warming means changing ecosystems, rising sea levels, greater flooding during storms, more prolonged droughts, melting glaciers, and disrupted animal migration.

How warming affect polar bears.

Polar Bears' Hunting Season Threatened by Break-Up of Ice Sheet. Cahal Milmo, The Independent (UK), 2006.9.15

The earlier annual break-up of sea ice is causing polar bears to spend more time on land in search of food.

The annual break-up of Arctic sea ice is getting progressively earlier each year, due to global warming. This is cutting short the spring hunting season for polar bears, which use floating banks of ice to reach their prey (seals and other marine mammals). The bears are spending more time on land, and encroaching on human settlements in search of food.

Australia - Climate Change

Australia's Changing Climate - The Age, 2004.5.26

Australia - Temperature

Australian Annual Mean Temperatures

Australian Bureau of Meteorology

Period

Max (°C)

Min (°C)

1913-1942

28.27

14.70

1943-1972

28.28

14.76

1973-2002

28.59

15.39

This table produced by adding average temperature departures from a 1961-1990 base temperature (at each weather station) to the average 1961-1990 base temperature as given by the following sources:

Australian Annual Mean Temperature Anomalies

Gives Australian annual average maximum and minimum temperatures as differences from 1961-1990 averages.

Record Warm Year for Australia in 1998

Gives the Australian annual average maximum and minimum temperatures for the 1961-1990 period as 28.45 and 15.17 °C respectively.

Australia - Rainfall

Average Annual Rainfall for Australia

Australian Bureau of Meteorology

Period

Australian average annual rainfall (mm)

1913-1942

435

1943-1972

440

1973-2002

504

Australia - Evaporation

Sunburnt Country is Not So Dry Now, Despite Rising Temperatures. Deborah Smith and Richard Macey, Sydney Morning Herald, 1 July 2004

Water evaporation from sources such as dams, lakes and swimming pools has been falling for three decades, despite rising temperatures.

Changes in Water Cycle through Australian Landscape. CRC for Greenhouse Accounting, 30 June 2004

Most scientists have long expected that as global average temperatures rise because of the enhanced greenhouse effect, pan evaporation would also increase. However, vapour pressure has increased with global temperatures, so relative humidity has remained about the same [and thus not caused an increase in pan evaporation].

World Temperature

Has the World Warmed? - US Global Change Research Information Office

The globally averaged temperature of the air at the Earth's surface has warmed between 0.3 and 0.6°C (about 0.5 and 1°F) since the late 19th century.

Global and Hemispheric Temperature Anomalies - Carbon Dioxide Information Analysis Centre, 2001

Trends in annual mean temperature anomalies for the globe show relatively stable temperatures from the beginning of the record through about 1910, with relatively rapid and steady warming through the early 1940s, followed by another period of relatively stable temperatures through the mid-1970s. From this point onward, another rapid rise similar to that in the earlier part of the century is observed.

The warming has varied in extent and magnitude across the globe and a few areas have even cooled since the nineteenth century.

Global (Near) Surface Temperatures

Period

Average global (near) surface temperature (°C)

1883-1912

13.68

1913-1942

13.85

1943-1972

13.94

1973-2002

14.17

This table produced by adding average temperature departures from a 1961-1990 base temperature (at each weather station) to the average 1961-1990 base temperature as given by the following sources:

Global Near Surface Temperatures. Hadley Centre

Gives annual global near-surface temperature as departures from a 1961-1990 average.

Global Temperature in 2003 Third Warmest.

Gives the average global surface temperature for the 1961-1990 period as 14.0 °C.

Hotter Cities

Global Warming Tipped to Produce Hot City Nights. ABC, 2004.6.17

The so-called "urban heat island" effect, of heat generated from buildings and vehicles being retained by asphalt and concrete at night, will intensify. "Cities that now release an average of 20 watts of heat per square metre will in future release 60 watts more."

Melting Ice

Greenland Ice-Melt 'Speeding Up'. David Shukman, BBC, 2000.7.28

Data from a network of automatic monitoring stations, run by Carl Boggild of the Geological Survey of Denmark and Greenland, show that the edges of the Greenland ice-sheet are melting up to 10 times more rapidly than earlier research had indicated.

Massive Surge in Disappearance of Arctic Sea Ice Sparks Global Warning. Michael McCarthy, David Usborne, The Independent (UK), 2006.9.15

Global warming is causing the extent of Arctic sea ice during Northern winters to shrink at an accelerating rate. Two separate studies by NASA, using different satellite monitoring technologies, both show a great surge in the disappearance of Arctic ice cover in the last two years.

Flooding

Expert Warns Flooding Will Increase. ABC, 2004.6.14

The number of people vulnerable to floods around the world is expected to rise to at least two billion by 2050, particularly in Asia, due to climate change and population growth.

The causes are extreme weather that develops as the climate changes, rising sea levels, continuing deforestation and a rise of the number of people working in flood-prone areas as the population increases.

From 1971-1995, floods affected more than 1.5 billion people, or 100 million a year, a total that includes 318,000 killed and more than 81 million left homeless.

The frequency of major flood disasters has risen. There were six in the 1950s; seven in the 1960s; eight in 1970s; 18 in the 1980s; and 26 in the 1990s.

Threat of Devastating Floods 'Will Double' by 2050. Mike Shanahan, Science Development Network, 2004.6.13

The number of people living in the path of potentially devastating floods is set to double - from one to two billion - within two generations unless adequate preventative steps are taken.

Each year, floods and weather-related disasters cost the global economy US$50-60 billion. These losses could be reduced if current spending on flood prevention and prediction were increased.

Whilst countries are generous with post-disaster relief, they are thrifty where preparedness is concerned, spending US$100 on relief for every US$1 that is spent on preparedness.

Water Hazards, Risks and Vulnerabilities in a Changing Environment (PDF). Janos Bogardi. United Nations University. 2004.4

Factors that have increased flooding and flood vulnerability:

Risk

Risk Reduction in the 21st Century (PDF). United Nations University. 2004.5

Population growth combined with a continued increase of consumption has led to overexploitation of the natural resources, manifested by widespread land degradation, erosion, deforestation, air, water, and soil pollution.

Resource utilization and the related production systems are so highly stressed that they cannot tolerate much variability in supply and demand. This increases their vulnerability to natural hazards.

We need to break the vicious cycle of overuse-intervention-more intervention, and establish long-lasting self sustaining comprehensive rehabilitation processes.

Two reasons why we should live in harmony with nature:

  1. Our earth's environment is driven by massive forces that are several orders of magnitudes higher than the range of energy we deal with. Thus human intervention and remedial action may not match processes once out of control.
  2. Our global environment is an extremely complex inter-connected system, where even a small change of energy or material flow, can affect the whole system. When this balance is disturbed, it could be the beginning of a chain reaction with consequences that are difficult to predict.

Biodiversity Loss

World Biodiveristy Loss

Imperilled Ecosystems. David Suzuki Foundation

A changing climate forces plants and animals to migrate in order to survive. However, most plant species are able to migrate at only one tenth of the speed required to keep up with human-induced climate change.

To make matters worse, human settlements and infrastructure have already subdivided ecosystem habitat into isolated patches. Climate change will make many of these patches uninhabitable for the species which live there, and they will be unable to escape.

Australian Biodiversity Loss

Climate Change Impacts on Biodiversity in Australia. Australian Government, 2002

There is evidence suggesting that the rate of climate change will be faster than the rate at which most species can adapt, either by migration or by changing their behaviour, physiology or form.

Coral reefs

Coral is dying apparently because of more frequent and severe heat waves that stress and bleach it, and also there are detrimental changes in sea-water chemistry caused by increasing amounts of carbon dioxide (CO2) in the atmosphere. Evidence suggests that with even mild warming (+2°C), tropical near-shore communities will change from coral-dominance to algal-dominance.

Near coastal marine systems

It is possible that plankton productivity could become significantly more variable in near coastal marine systems, and that change could have flow-on effects to system ecology and productivity.

Rangelands

There is likely to be a decrease in rangeland productivity, an increasing risk of degradation, increasing sensitivity to disturbance, a change in ecosystem function, and alteration to plant and animal community composition.

Alpine regions

Large reductions in snow cover are likely to lead to declines in alpine flora and fauna as a result of changes to habitats, alterations in fire regimes and incursion of feral animals and weeds.

Temperate forests

As well as changes in vegetation composition in temperate forests, it is likely that changes in structure, productivity and foliage quality will have flow-on effects to other components of biodiversity. Additionally, likely increases in fire frequency and intensity will have also have impacts.

Tropical rainforests

Highland rainforest environments, the habitat for many of the region's endemic vertebrates, may decrease in area by 50% even with only a 1°C warming.

A 1°C increase in average temperatures is predicted to decrease the bio-climatic range of endemic fauna species by about one-third (37%). A rise of 3.5°C will reduce bioclimatic range to an average of 11% of current area, and will completely eliminate the current bioclimates occupied by 30 species of endemic vertebrates.

Recommendation:

Make species and eco-systems more resilient to climate change by reducing other threats, eg pest animals, disease, weeds, fire, and sediment and nutrient discharge (which affects the Great Barrier Reef).

Runaway Global Warming

Accelerated Global Warming and Atmospheric CO2 Emissions. Hydrogen Now Journal

Evidence suggests that global warming may not be a linear response to rising CO2 levels. There is a danger that at some point we will cross a threshhold when global warming accelerates. By continuing to increase the amount of CO2 in the atmosphere we are getting closer to that point.

Runaway Methane Global Warming. Hydrogen Now Journal, 2001.11

Global warming could lead to the release of methane currently trapped in unstable methane hydrate deposits in the Arctic. This would accelerate global warming causing further release of methane in a runaway effect.

Preventing Climate Change

World's Most Wanted: Climate Change. John Ashton, BBC, 2006.9.8

We need to pursue a stable climate through urgent, if costly, construction of a low carbon global economy because not doing so will cost much more.

To respond to climate change, we need is an investment internationally of political imagination backed up by public resources on the scale that the public would expect for more traditional aspects of national security.

Governments must build the avenues of trust and opportunity that will divert investment from high carbon to low carbon infrastructure; negotiate the agreements that will enable us to do that cost-effectively and without divisive market distortions; design and mobilise coalitions of mutual interest across sectoral and cultural boundaries to transform the way we supply and consume energy, achieve mobility, and use land.

And they will need to do all of this very fast. It is now becoming increasingly clear that it is what we do in the next 15 years that matters most.

Links

Wikipedia - Climate Change

2007.2.23