Not only posing significant risks for Earth’s natural systems, the effects of global warming on humans and human systems have only recently begun receiving the expanded attention they critically require.
From hazardous effects causing potential loss of life, injury, or other negative health impacts, to the potential exposure of social, economic, and infrastructure assets to adverse impacts, global warming places vulnerable human lives and systems in dangerous jeopardy.
The IPCC Brings New Focus on Human Risks
Established by the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP) in 1988, the Intergovernmental Panel on Climate Change (IPCC) is mandated “to provide the world community with the most up-to-date and comprehensive scientific, technical, and socio-economic information about climate change.” IPCC Assessment Reports have significantly motivated governments’ response to climate change, including the international adoption of the United Nations Framework Convention on Climate Change and the Kyoto Protocol.
With a new focus on human risks, the March 2015 final publication of the IPCC’s Fifth Assessment Synthesis Report (SYR) brings a broadly improved, wide-ranging analysis to the international global warming round-table. Referring to the upcoming United Nations Climate Change Conference in Paris (COP21) from 30 November–11 December 2015, Ismail El Gizouli, Acting Chair of the IPCC said, “The (IPCC AR5) Synthesis Report, distilling the work of hundreds of experts, is an invaluable tool and resource for policymakers as the world prepares to finalize a global agreement on climate change later this year.”
Based on the IPCC AR5 Summary for Policymakers (SPM) , the following synthesis of the effects of global warming on humans is presented as the most up-to-date evaluation currently available.
Effects of Global Warming on Humans
Specifically addressed in the IPCC AR5 Working Group II (WGII) report published in 2014, effects of global warming on humans and human systems were assessed by both global sectors and regions. Sectors assessed for specific effects included freshwater resources, terrestrial and ocean ecosystems, coasts, food, urban and rural areas, energy and industry, human health and security, and livelihoods and poverty. Regions assessed included Africa, Europe, Asia, Australasia, North America, Central and South America, Polar Regions, Small Islands, and the Ocean.
“Compared to past WGII reports,” states the IPCC, “the WGII AR5 assesses a substantially larger knowledge base of relevant scientific, technical, and socioeconomic literature. Increased literature has facilitated comprehensive assessment across a broader set of topics and sectors, with expanded coverage of human systems, adaptation, and the ocean.”
Effects of global warming on humans are identified in the IPCC AR5 as “Key Risks” based on the following criteria: “Large magnitude, high probability, or irreversibility of impacts; timing of impacts; persistent vulnerability or exposure contributing to risks; or limited potential to reduce risks through adaptation or mitigation.” Impacting every sector and region, Key Risks related to the effects of global warming on humans include the following:
• Risk of death, injury, ill-health, or disrupted livelihoods in low-lying coastal zones and small island developing states and other small islands, due to storm surges, coastal flooding, and sea level rise.
• Risk of severe ill-health and disrupted livelihoods for large urban populations due to inland flooding in some regions.
• Systemic risks due to extreme weather events leading to breakdown of infrastructure networks and critical services such as electricity, water supply, and health and emergency services.
• Risk of mortality and morbidity during periods of extreme heat, particularly for vulnerable urban populations and those working outdoors in urban or rural areas.
• Risk of food insecurity and the breakdown of food systems linked to warming, drought, flooding, and precipitation variability and extremes, particularly for poorer populations in urban and rural settings.
• Risk of loss of rural livelihoods and income due to insufficient access to drinking and irrigation water and reduced agricultural productivity, particularly for farmers and pastoralists with minimal capital in semi-arid regions.
• Risk of loss of marine and coastal ecosystems, biodiversity, and the ecosystem goods, functions, and services they provide for coastal livelihoods, especially for fishing communities in the tropics and the Arctic.
• Risk of loss of terrestrial and inland water ecosystems, biodiversity, and the ecosystem goods, functions, and services they provide for livelihoods.
Assessing Human Risks by Sectors
Although a limited range of positive effects of global warming on humans have been identified, the overwhelming majority of effects are increasingly dangerous. Many global warming-related risks are limited to particular sectors, while other impacts can be expected to have a domino-effect, cascading into other sectors.
• Freshwater resources — Global populations are increasingly experiencing water scarcity, and areas affected by major river floods are experiencing increases. Although water resources at high latitudes are increasing, renewable surface water and groundwater resources are declining significantly in most dry subtropical regions, droughts are also increasing, and competition for water is intensifying.
Raw water quality is declining, affecting drinking water quality even with conventional treatment, due to increased temperature, as well as sediment, nutrient, and pollutant runoff during heavy rain and floods. Also, droughts are contributing to airborne pollutants affecting freshwater resources. Freshwater ecosystems are likewise being negatively impacted, affecting freshwater-related livelihoods.
• Coastal systems and low-lying areas — As the sea level rises, coastal systems and low-lying areas are increasingly experiencing submergence, coastal flooding, and coastal erosion. Coastal populations, assets, and ecosystems are facing significant risk increase due to population growth, economic development, and urbanization. Some low-lying developing countries and small island states are expected to face damage and adaptation costs of several percentage points of GDP.
• Marine systems — Global warming-related marine-species redistribution and marine-biodiversity reduction in sensitive regions impacts productivity of fisheries and other ecosystem services. Increasing ocean warming is causing spatial shifts of marine species, with resultant high-latitude invasions and high local-extinction rates in the tropics and semi-enclosed seas. Species and catch numbers are increasing, on average, at mid and high latitudes and decreasing at tropical latitudes. Oxygen minimum zones, anoxic “dead zones,” and ocean acidification increasingly impact marine ecosystems and fish habitats, with negative consequences for fisheries, livelihoods, and food security.
• Food security and food production systems — Major crop production is negatively impacted as temperatures are rising. The negative effects of global warming on humans may be most significant on food supplies and security. Wheat, rice, and maize production in tropical and temperate regions are anticipated to vary widely in yields, with severe yield impacts significantly increasing after 2050, depending on global temperatures. An increase of ~4°C or more above late-20th-century levels, combined with increasing food demand, risks negatively impacting all aspects of food security, including access, utilization, and price stability.
• Urban areas — Urban areas pose multiple risks for people, assets, economies, and ecosystems. These risks include heat stress, extreme precipitation, inland and coastal flooding, landslides, air pollution, drought, and water scarcity. For people living in poor-quality housing and exposed areas, or in areas with insufficient infrastructure and services, risk are especially high.
• Rural areas — Negative effects of global warming on humans in rural areas occur through declines in water availability and supply, food security, and agricultural incomes. As food production areas shift due to global temperatures, low-income people in rural areas will increasingly suffer, especially female-headed homes, people with limited education, access to infrastructure, land, and/or modern agricultural methodologies.
• Key economic sectors and services — Global impacts on economic sectors are variable, with limitations to the accuracy of future estimates of global warming impacts. However, as temperatures increase, the likelihood of annual economic loss increases. For example, energy required for heating is decreasing as global temperatures rise, but the energy demand for cooling in the residential and commercial sectors is rising. Depending on renewable energy resources and locations, such as water flow, wind, solar irradiation, etc., energy sources are being impacted variably. Losses are increasing with more severe and frequent extreme weather events, challenging insurance systems to offer affordable coverage while raising more risk-based capital, particularly in developing countries.
• Human health — Effects of global warming on humans’ health includes exacerbating health problems that already exist, increases in ill-health in many regions and especially in developing countries with low-income, and greater likelihood of injury, disease, and death. These risks are due to more intense heat waves and fires, and increased likelihood of under-nutrition resulting from diminished food production in poor regions. As global temperatures rise, normal human activities are compromised, such as farming or working outdoors. Risks from lost work capacity and reduced labor productivity in vulnerable populations also increase, as well as increased risks from vector-, food-, and water-borne diseases.
• Human security — Increasingly displacing people, global warming-related extreme weather events in both rural and urban areas expose vulnerable populations to high risk of social upheaval. Changes in migration patterns are occurring as populations become displaced due to weather-related impacts. Violent conflicts are also at risk of rising, due to climate change impacts on economic stability.
National security policies are expected to reshape due to climate change impacts on critical infrastructure and territorial integrity. For example, small island states and states with extensive coastlines face risks of territorial loss of integrity due to the rising sea level submerging land. Changes in sea ice, shared water resources, and common pelagic fish stocks are also facing impact, with the resulting potential for transboundary rivalry and conflict.
• Livelihoods and poverty — Economic effects of global warming on humans are significant, making poverty reduction more difficult and further eroding food security for the poor. Climate change impacts economic growth, creating new poverty traps for more people, especially in urban areas and regions experiencing food insecurity. Increasing socioeconomic inequality, in both developed and developing nations are impacting both rural and urban areas. Wage-earners in low-income households are facing increasing risks due to food prices increasing as food insecurity rises.
Mitigation and Adaptation Strategies
Significantly mitigating the effects of global warming on humans requires coordinated adoption of climate adaptation strategies. All across the globe, efforts are being focused on identifying and implementing adaptation strategies. Becoming embedded in planning processes, integrated within existing programs such as disaster risk management and water management, adaptation strategies are increasingly being adopted to mitigate the effect of global warming on humans. Social, institutional, and ecosystem-based measures are increasingly being recognized and valued, accumulating across regions and governments, from the public and private sectors to the smallest, remotest communities.
Highlighting significant strategies, the IPCC AR5 includes examples of adaptation being adopted across the following regions:
• Africa — Most national governments are now 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.
• Europe — Adaptation policy has been developed across all levels of government, with some adaptation planning integrated into coastal and water management, into environmental protection and land planning, and into disaster risk management.
• Asia — Adaptation is being facilitated in some areas through mainstreaming climate adaptation action into subnational development planning, early warning systems, integrated water resources management, agroforestry, and coastal reforestation of mangroves.
• Australasia — Planning for sea level rise, and in southern Australia for reduced water availability, is becoming widely adopted. Planning for sea level rise has evolved considerably over the past 2 decades and shows a diversity of approaches, although its implementation remains piecemeal.
• North America — Governments are engaging in incremental adaptation assessment and planning, particularly at the municipal level. Some proactive adaptation is occurring to protect longer-term investments in energy and public infrastructure.
• Central and South America — Ecosystem-based adaptation including protected areas, conservation agreements, and community management of natural areas is occurring. Resilient crop varieties, climate forecasts, and integrated water resources management are being adopted within the agricultural sector in some areas.
• Arctic — Some communities have begun to deploy adaptive co-management strategies and communications infrastructure, combining traditional and scientific knowledge.
• Small Islands — Community-based adaptation has been shown to generate larger benefits when delivered in conjunction with other development activities.
• The Ocean — International cooperation and marine spatial planning are starting to facilitate adaptation to global warming, although with limitations due to spatial scale and international governance issues.
The Positive Effect of Humans on Global Warming
The IPCC AR5 clearly identifies and defines the wide-ranging scope of significant negative effects of global warming on humans. From hazardous effects causing potential loss of life, injury, or other negative health impacts, to the potential exposure of social, economic, and infrastructure assets to adverse impacts, the effects of global warming on humans are clearly and significantly negative.
However (and thankfully), abandoning old capitalistic and nationalistic get-rich-quick ideologies, collaborating on never-before-seen international levels for the purpose of achieving the greater good of humanity, and all of the adaptation strategies being adopted on local levels across the globe are among the significant positive effects of global warming on humans. As they say, what goes around, comes around. The challenge, now, is for humans to have significant and positive effect on global warming.
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