General Climate Impacts
The Indo-Pacific region is already experiencing climate change; just how bad the effects will be in the coming decades will depend on the rise or fall of total greenhouse gas emissions. Regardless, a certain amount of change is already locked in due to past and continued greenhouse gas emissions, with significant effects on the severity and patterns of seasonal monsoon storms, changes in river flows due to changes in snowpack and melt, and sea level rise. These effects will have an impact on agriculture, energy, human health, and ecological systems across the region.
Summary of How Climate Change Will Affect the Indo-Pacific Region
Temperature: Average temperatures are projected to increase more rapidly closer to the poles than in the tropics. However, extraordinarily high temperatures will be more common for tropical areas that experience less background variation. Many areas will experience extreme heat levels much more frequently and for longer periods than in the past.
Precipitation: Annual precipitation rates are projected to increase across the region, but with greater variation. In addition, the frequency and intensity of extreme precipitation events is likely to increase.
Sea level rise: Global sea levels are expected to rise an average of 0.9m (3 ft) to 1.6m (5 ft) by 2100. Because the melting of ice sheets will likely lag behind other climatic changes, sea level rise will likely be slow in the near term but accelerate throughout the coming centuries. Even a relatively modest rise can be an existential threat to island states and delta populations.
Agriculture: The impacts of climate change on agriculture will be varied, with some areas potentially seeing positive change, at least in the short term, while others suffer. Higher temperatures will increase heat stress for certain crops and increase water demand, though the heat may extend growing seasons in colder climates. Increased variability in precipitation will affect rainfed agriculture and increase drought risk. Similarly, greater seasonal variation in river flows will increase the need for water storage to maintain large swaths of irrigated cropland across the region and is likely to put greater demand on groundwater resources. On the other hand, regions downstream of glaciated highlands may see increased irrigation water availability as these long-term stores of water are released, though there may also be destructive floods. Projections of the impact of global warming on crop yields remain uncertain, in part due to uncertainty around the net effects of CO2 fertilization.
Fisheries: Extensive coral reef bleaching is likely to occur under 2ºC of warming, severely damaging coastal fisheries and reducing tourism potential.
Health: Extreme temperatures are a known mortality risk, especially for elderly populations, and a number of countries in the region have aging populations (especially Japan, China, and the United States). Though tropical populations are more resilient to extreme heat, lack of air conditioning in poorer areas limits options for reprieve. Extreme heat may also compound risk to tropical cyclones, as severe storms lead to widespread blackouts. More frequent wildfires may negatively impact air quality, while higher temperatures will increase the range of disease vectors, such as mosquitoes.
Energy: Greater variability in river flows may limit hydropower output during the dry season and put competing demands for flood control on reservoirs during the wet season, though higher total precipitation may increase overall hydropower output. High temperatures may also limit energy generation of thermal power plants, which rely on cooling water to operate.
Security: Increasing water scarcity, sea level rise, and disasters will likely drive increased migration, which may exacerbate existing tensions and strain governments. Increased energy insecurity may also raise inter-state tensions. Shifting patterns of energy, food, and water availability, as well as sudden onset disasters, may challenge even strong governments, let alone weak or corrupt regimes.