Climate change will likely have significant impacts around the world. For instance, sea-level rise will compound pressures that coastal communities already face, including erosion, storms, and pressures from development. In arid and semi-arid regions, relatively modest changes in precipitation can have large impacts on already limited water supplies. Most projections of future impacts do not address what could happen if warming continues beyond 2100, which is inevitable if steps to reduce emissions are not taken, or if the rate of change accelerates. Even if greenhouse gas emissions are reduced, some further warming is unavoidable, in that the amount of CO2 released into the atmosphere in the next 30 years is expected to double or triple. Global surface temperatures in 1999 set a new record for the period of instrumental measurements, according to the NASA Goddard Institute for Space Studies. The global temperature exceeded that of the previous record year, 1995, by about 0.2°C (0.4°F). In the near term, agriculture and forestry may benefit, but hotter and drier conditions increase the potential for crop distributions to change. Areas around the world already having water shortages or water quality problems will see these problems worsen.

In the latest report of IPCC's Working Group II, which addresses the vulnerability of socio-economic and natural systems to climate change, scientists predict glaciers and polar icecaps melting, countless species of animals, birds and plant life dying out, farmland turning to desert, coral reefs destroyed, and small island states submerged by the sea. The final report of Working Group II addresses, among others issues:

• Water Resources - the effects of climate change on water supplies, water demands, and flood and drought hazards;
• Agriculture and Food Supply - the effects of climate change on crop yields and food supply;
• Terrestrial Ecosystems - the effects of climate change on forest, grassland, desert, aquatic, and alpine ecosystems and their wildlife;
• Coastal Zones and Marine Ecosystems - the effects of climate change and sea level rise on coastal zones and marine ecosystems;
• Human Settlements, Energy and Industry - vulnerabilities of human settlements, energy and industry to climate change, including potential changes in extreme weather hazards;
• Insurance and Other Financial Services - trends in economic and insured losses from extreme climate events and vulnerabilities of the financial sector to climate change; and
• Human Health - the effects of climate change on human health, including changes in exposure to infectious diseases (e.g. malaria, Dengue) and death rates and illness associated with heat stress and cold weather.
  

The report addresses adaptation options for each of these areas, and includes reports on regional concerns, vulnerabilities and adaptive capacities in: Africa, Asia, Australia and New Zealand, Europe, Latin America, North America, Polar Regions (Arctic and Antarctic) and Small Island States. According to the report, “projected climate changes during the 21st century have the potential to lead to future large-scale and possibly irreversible changes in Earth systems, resulting in impacts on continental and global scales.'' The Summary for Policymakers adds that "climate change in polar regions is expected to be among the greatest of any region on the Earth." Already, the extent and thickness of Arctic sea ice has decreased, permafrost has thawed and the distribution and abundance of species has been affected. The trends may continue even long after greenhouse gas emissions are stabilized, causing irreversible impact on ice sheets, global ocean circulation and sea levels.

The information presented above can be separated into biophysical and socio-economic impacts. These are discussed briefly below. This is not an exhaustive description of studies to date. Rather, it is a brief outline of recent discussions on biophysical and socio-economic impacts related to climate change. The aim is to promote discussion and encourage knowledge sharing in relation to climate change impacts. It is hoped that through this brief introduction, network users will be prompted to share their reports, case studies and experiences in relation to biophysical and socio-economic impacts of climate change at variable scales.

Principle Climate Drivers and Associated Biophysical Impacts

 

There are several biophysical impacts attributed to a changing climate. However, due to the limitations of scientific knowledge in relation to predicted rates of climate change, it is difficult to foresee impacts in quantifiable terms. Despite this, there is general scientific consensus that the following biophysical impacts will occur:

• Decline in species diversity
• Changes in the hydrological cycle

Projections on future biodiversity levels show an overall decrease as a result of multiple pressures. Because many of the impacts of biodiversity are occurring independent of climate change, McCarthy et al (2001) suggest that the question becomes, ‘How might climate change enhance or inhibit these loses in biodiversity?” At present, there is limited evidence to suggest that climate change will slow the loss of biodiversity; rather research indicates that increasing CO2 levels will favour invasive species and that increased nitrogen loads in the biological cycle will reduce diversity of plants and animals. The projected levels of diversity loss are variable relative to the climate change scenario applied.

Principle Climate Drivers and Associated Socio-economic Impacts

Human societies are, by nature, adaptable. Over centuries humans have been adjusting to changes in their social and physical environments. However, climate change poses a significant challenge for human societies. The nature of climate change will see multiple alterations to social and ecological environments. As a result, there are a number of socio-economic impacts that are projected to occur (summarised in Table 1). These impacts have brought adaptation, assessment and planning to the fore.

The geophysical response to climate change varies spatially and temporally. Thus, Table 1 summarises general impacts against selected responses. Detailed information on response-impact relations is available from the suggested links and documents below.

Table 1: Socio-economic Impacts of Geophysical Reponses to Climate Change

Geophysical Response to Climate Change	Socio-economic Impact
Warmer climatic conditions	- Increased number of heat related illnesses in the elderly and poor - Increased energy demand, due to higher air conditioner use, increasing the risk of blackouts - Spread of water borne, vector borne and food borne diseases - Changes in levels of agricultural production
Decline in Rainfall	- Changes in agricultural production - Increased threat to urban water security - Decline in aquifer recharge
Increase in Rainfall	- Increased flood, landslide, avalanche, and mudslide damage - Increased soil erosion - Increased recharge to floodplain aquifers
Increased occurrence of extreme weather events	- Numerous problems for industry and infrastructure - Societies most at risk are those with high exposure to extreme climatic events with limited adaptive capacity

 

Principle Climate Drivers and Associated Biophysical and Socio-Economic Coastal Impacts

In recent Intergovernmental Panel on Climate Change (IPCC) assessments it has been emphasised that climate change brings with it other implications for coasts, in addition to the threat of sea-level rise (Table 2). These climate change impacts include possible increases to sea-surface temperatures, greater variability in the patterns of rainfall and runoff, possible changes to wave climate, changes to the frequency, intensity and duration of storms, and changes to ocean chemistry associated with global warming, particularly ocean acidification. There is particular concern about extreme weather events (floods, droughts and cyclones) that pose additional threats to human infrastructure and settlements in the coastal zone. The tables below provide a general summary of potential socio-economic impacts in global coastal regions (Table 3) and the principle climate drivers and direct and indirect impacts on the coast of Australia (Table 2).

 

Table 2. Principal climate change drivers and possible direct and indirect impacts on the coast of Australia, synthesised from IPCC and SURVAS summaries, with tentative indication of confidence level in their likelihood of occurrence (very high [VHC], high [HC], medium [MC], low [LC] or very low [VLC] confidence).

Climate Change (Driver)	Principle durect physical and ecosystem effects	Potential secondary and indirect impacts
Sea-level change [VHC] (principally rise)	Increased coastal erosion [VHC] Increased inundation of coastal wetlands and lowlands [MC] Increased risk of flooding and storm damage [HC] Increased salinisation of surface and ground waters. [MC]	Infrastructure and economic activity impacted [MC] Displacement of vulnerable populations [LC]
Sea-surface temperature [HC] (principally rise)	Increased coral bleaching [HC] Pole ward species migration [LC] Increased algal blooms [LC]	Impact on tourism [LC] Possible health impacts [LC]
Altered precipitation and runoff [MC] (local increases/decreases)	Altered river sediment supply [MC] Altered lowland flood risk [MC] Water quality/nutrient impacts [LC]	Implications for erosion and flooding [LC]
Altered wave climate [LC] (uncertain)	Altered wave run-up [VLC] Altered erosion and accretion [LC]	Further erosion [LC]
Storm frequency and intensity changes [LC] (uncertain)	Increased waves and surges [LC] Altered cyclone zones [LC]	Further storm damage [LC]
Increases in CO2 concentration in the atmosphere [VHC] and ocean [HC]	Increased ocean acidification [HC] Increased disruption to food chains (eg. Southern Ocean) [MC]	Less resilient reefs [LC] Impaired movement and function of high oxygen demand fauna (eg. squid, fish) [MC]

 

Table 3: Socio-economic Impacts of Climate Change in Coastal Zones

	More Frequent Floods	Erosion of coast	Inundation by sea water	Increase in water table	Intusion of salt water	Change in biological processes
Water resources			√	√	√	√
Agriculture	√		√	√	√
Human health	√		√			√
Fisheries	√	√	√		√	√
Tourism	√	√	√			√
Human settlements	√	√	√	√

Source: UNFC (2006)