A couple of weeks ago, the IPCC released its evaluation of the risks and benefits associated with climate change. The report received scanty mention in the press even though "human interference with the climate system is occurring and climate change poses risks for human and natural systems". The report is not the most readable of documents, though it does contain some fascinating graphs and tables, so I have taken it upon myself to extract some of the key points, specially for African and other developing countries. Apologies for the length but it's difficult to know what else to leave out!
For most economic sectors, the impacts of drivers such as changes in population, age structure, income, technology, relative prices, lifestyle, regulation, and governance are projected to be large relative to the impacts of climate change. Climate change is projected to reduce energy demand for heating and increase energy demand for cooling in the residential and commercial sectors. Climate change is projected to affect energy sources and technologies differently, depending on resources (e.g., water flow, wind, insolation), technological processes (e.g., cooling), or locations (e.g., coastal regions, floodplains) involved.
Impacts from recent climate-related extremes, such as heat waves, droughts, floods, cyclones, and wildfires, reveal significant vulnerability and exposure of some ecosystems and many human systems to current climate variability. Impacts include alteration of ecosystems, disruption of food production and water supply, damage to infrastructure and settlements, morbidity and mortality, and consequences for mental health and human well-being. Climate-related hazards affect poor people’s lives directly through impacts on livelihoods, reductions in crop yields, or destruction of homes and indirectly through, for example, increased food prices and food insecurity. Violent conflict increases vulnerability to climate change. For countries at all levels of development, these impacts are consistent with a significant lack of preparedness for current climate variability in some sectors.
Freshwater-related risks of climate change increase significantly with increasing greenhouse gas concentrations. In many regions, changing precipitation or melting snow and ice are altering hydrological systems, affecting water resources in terms of quantity and quality. Glaciers continue to shrink almost worldwide due to climate change, affecting runoff and water resources downstream. The fraction of global population experiencing water scarcity and the fraction affected by major river floods will increase with the level of warming in the 21st century. Climate change is projected to reduce renewable surface water and groundwater resources significantly in most dry subtropical regions, intensifying competition for water among sectors. In presently dry regions, drought frequency will likely increase by the end of the 21st century; in contrast, water resources are projected to increase at high latitudes. Climate change is projected to reduce raw water quality and pose risks to drinki ng water quality even with conventional treatment, due to interacting factors: increased temperature; increased sediment, nutrient, and pollutant loadings from heavy rainfall; increased concentration of pollutants during droughts; and disruption of treatment facilities during floods.
Many terrestrial, freshwater, and marine species have shifted their geographic ranges, seasonal activities, migration patterns, abundances, and species interactions in response to ongoing climate change. While only a few recent species extinctions have been attributed as yet to climate change, natural global climate change at rates slower than current anthropogenic climate change caused significant ecosystem shifts and species extinctions during the past millions of years. A large fraction of both terrestrial and freshwater species faces increased extinction risk under projected climate change during and beyond the 21st century, especially as climate change interacts with other stressors, such as habitat modification, over-exploitation, pollution, and invasive species. Some species will adapt to new climates. Those that cannot adapt sufficiently fast will decrease in abundance or go extinct in part or all of their ranges.
Global marine-species redistribution and marine-biodiversity reduction in sensitive regions will challenge the sustained provision of fisheries productivity and other ecosystem services. Spatial shifts of marine species due to projected warming will cause high-latitude invasions and high local-extinction rates in the tropics and semi-enclosed seas. Species richness and fisheries catch potential are projected to increase, on average, at mid and high latitudes and decrease at tropical latitudes. The progressive expansion of oxygen minimum zones and anoxic “dead zones” is projected to further constrain fish habitat. Ocean acidification poses substantial risks to marine ecosystems, especially polar ecosystems and coral reefs.
Increased tree mortality and associated forest dieback is projected to occur in many regions, due to increased temperatures and drought. Forest dieback poses risks for carbon storage, biodiversity, wood production, water quality, amenity, and economic activity. Based on many studies covering a wide range of regions and crops, negative impacts of climate change on crop yields have been more common than positive impacts. The smaller number of studies showing positive impacts relate mainly to high latitude regions. Climate change has negatively affected wheat and maize yields for many regions and in the global aggregate. Effects on rice and soybean yield have been smaller in major production regions and globally. Several periods of rapid food and cereal price increases following climate extremes in key producing regions indicate a sensitivity of current markets to climate extremes among other factors.
At present the world-wide burden of human ill-health from climate change is relatively small compared with effects of other stressors and is not well quantified. However, there has been increased heat-related mortality and decreased cold-related mortality in some regions as a result of warming. Local changes in temperature and rainfall have altered the distribution of some water-borne illnesses and disease vectors. People who are socially, economically, culturally, politically, institutionally, or otherwise marginalized are especially vulnerable to climate change and also to some adaptation and mitigation responses. This heightened vulnerability is rarely due to a single cause. Until mid-century, projected climate change will impact human health mainly by exacerbating health problems that already exist. Climate change is expected to lead to increases in ill-health in many regions and especially in developing countries with low income, as compared to a baseline without climate chang e. The combination of high temperature and humidity in some areas for parts of the year is projected to compromise normal human activities, including growing food or working outdoors.
Many global risks of climate change are concentrated in urban areas. Heat stress, extreme precipitation, inland and coastal flooding, landslides, air pollution, drought, and water scarcity pose risks in urban areas for people, assets, economies, and ecosystems. Risks are amplified for those lacking essential infrastructure and services or living in poor-quality housing and exposed areas. Major future rural impacts are expected in the near-term and beyond through impacts on water availability and supply, food security, and agricultural incomes, including shifts in production areas of food and non-food crops across the world. These impacts are expected to disproportionately affect the welfare of the poor in rural areas, such as female-headed households and those with limited access to land, modern agricultural inputs, infrastructure, and education.
Due to sea-level rise projected throughout the 21st century and beyond, coastal systems and low-lying areas will increasingly experience adverse impacts such as submergence, coastal flooding, and coastal erosion. The population and assets projected to be exposed to coastal risks as well as human pressures on coastal ecosystems will increase significantly in the coming decades due to population growth, economic development, and urbanization.
Climate change is projected to increase displacement of people. Displacement risk increases when populations that lack the resources for planned migration experience higher exposure to extreme weather events, in both rural and urban areas, particularly in developing countries with low income. Land inundation due to sea-level rise poses risks to the territorial integrity of small-island states and states with extensive coastlines. Some transboundary impacts of climate change, such as changes in sea ice, shared water resources, and pelagic fish stocks, have the potential to increase rivalry among states. Climate-change impacts are projected to slow down economic growth, make poverty reduction more difficult, further erode food security, and prolong existing and create new poverty traps. Climate-change impacts are expected to exacerbate poverty in most developing countries and create new poverty pockets in countries with increasing inequality, in both developed and developing countrie s. In urban and rural areas, wage-labor-dependent poor households that are net buyers of food are expected to be particularly affected due to food price increases, including in regions with high food insecurity and high inequality, although the agricultural self-employed could benefit.
The report makes some broad recommendations for governments but none that organisations or individuals can use to mitigate the risk. In Africa, most national governments are initiating governance systems for adaptation. Disaster risk management, adjustments in technologies and infrastructure, ecosystem-based approaches, basic public health measures, and livelihood diversification are reducing vulnerability, although efforts to date tend to be isolated.
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