Pastures and Grazing
Pastures in higher rainfall areas are likely to benefit from higher carbon dioxide concentrations, but benefits may be negated by higher temperatures and decreases in rainfall. If rainfall decreased by more than 10 per cent in winter and spring – the main growing season for pastures – forage and animal production would decline, despite the higher concentrations of carbon dioxide.
Warmer temperatures will also increase the risk of heat stress in sheep and cattle. In dairy cattle, annual milk losses are likely to be between 250 and 310 litres per cow, depending on the rate of warming.
Horticulture and Viticulture
A projected decrease in frost frequency and severity would reduce the risk of damage to those fruits that are sensitive to frost late in the growing season. However, temperate fruits that require winter chilling to ensure normal bud-burst and fruit set are at risk of lower yields and reduced fruit quality. Climate change is likely to affect wine regions – including accelerated ripening, the need for increased irrigation, and opportunities for cultivating new grape varieties.
Broad acre cropping is likely to benefit from higher carbon dioxide concentrations, but these benefits may be negated by higher temperatures and reduced rainfall. Likely reductions in water resources may reduce the amount of water available for irrigation, while at the same time, irrigation requirements may increase as temperatures and evaporation rates increase.
Human settlement has dominated environmental change, and will continue to be a significant issue in the future. With the additional effects of climate change, human influences will become more severe as ecosystems progressively lose their natural protective mechanisms.
Climate change is already affecting plants and animals. Preliminary research of the potential effect on the distribution of fauna species indicated that most species are likely to suffer reduced habitat ranges under climate change scenarios. Of those species, more than half are predicted to lose between 90 and 100 per cent of their range, with a warming of 3C. Studies of selected flora suggest there may also be reductions in the ranges of plant habitats.
Ecosystems and species will be forced to respond directly to changing climatic conditions, and, at the same time will have to cope with, and adapt to, other climate-induced changes in land use and pests and diseases, particularly invasions by introduced species.
Many of ecosystems have a limited ability to adapt to climate change. Those restricted to small geographic areas, or unable to migrate fast enough to keep pace with shifting climatic zones, will be particularly vulnerable. However, some ecosystems and species will be advantaged or unaffected by climate change.
Climate change will impact on coastal areas through sea-level rise, increased temperatures and changing storm patterns. Although the exact nature of impacts are difficult to predict, many natural systems, including estuaries, coastal vegetation, wetlands and reefs are likely to have difficulty adapting to climate change, and may become increasingly vulnerable. Current settlement and development trends in coastal areas are likely to lead to greater community risk and insurance exposure to current and future hazards.
Alpine ecosystems and species are highly adapted to their environment, and are extremely sensitive to changes in climate. Decreasing snow cover, increasing risk of fire and invasion by weeds and other species will have a serious impact. Species whose habitat is located in the highest elevations and coldest environments will have nowhere to retreat to as the climate warms.
A range of direct and indirect climate change impacts may affect communities. Flooding and sea-level rise, heatwaves, water shortages, increased frequency and intensity of storms, greater air pollution and higher urban temperatures pose the greatest threats.
Climate change may have wide-ranging effects on human health. There is concern over the direct effects of higher summer temperatures and heatwaves; increased risk of respiratory problems, water quality issues for drinking water; and higher levels of food- and water-borne disease.
Climate change could also significantly impact on buildings and infrastructure. Higher temperatures and humidity, and greater risk of flooding and subsidence could lead to the deterioration of buildings, bridges and other structures, and the disruption of road, rail and power supplies. These impacts would carry significant economic costs. The insurance and finance industries are starting to re-evaluate risks, due to the possibility of more frequent and destructive storms.
Small alterations in average climate conditions are expected to generate larger changes in extreme weather events. The number of days over 35°C, and longer and more intense droughts, are expected to increase in frequency due to climate change. Extreme weather events may also lead to increased injuries or deaths, property and environmental damage.
The impacts of climate change affect all parts of the world. For example, the impacts of climate change on many low-lying Pacific Islands, which are highly vulnerable to climate change, could have serious flow-on effects for many countries. Climate change may affect countries' agricultural production, market prices and access to financial services, as well as the potential for flows of environmental refugees. Market changes in particular, offer both risks and opportunities for businesses, but more information is required before we are able to plan for such changes.