IPCC - Climate Change - Impacts, Adaptation, Vulnerability


North American Chapter 26 Excerpt from the Executive Summary

North America's climate has changed and some societally-relevant changes (e.g., spring snowpack) have been attributed to human causes. Recent climate changes and extreme events demonstrate that people and places are vulnerable in different ways. 

Many climate stresses that carry risk – particularly related to severe heat, heavy precipitation and declining snowpack – will increase in frequency and/or severity in North America in the next decades. The higher level of warming would present additional and substantial risks and adaptation challenges across a range of sectors. We highlight below key findings on impacts, vulnerabilities, projections, and adaptation responses relevant to specific North American sectors: ecosystems, water, agriculture, human health, urban and rural settlements, infrastructure and the economy. We then highlight challenges and opportunities for adaptation, and future risks and adaptive capacity for three key climate-related risks. 

North American ecosystems are under increasing stress from rising temperatures, CO2 concentrations, and sea-levels, and are particularly vulnerable to climate extremes. Climate stresses occur alongside other anthropogenic influences on ecosystems, including land-use changes, non-native species, and pollution, and in many cases will exacerbate these pressures.

Water resources are already stressed in many parts of North America due to non-climate change anthropogenic forces, and are expected to become further stressed due to climate change.

Effects of temperature and climate variability on yields of major crops have been observed. Projected increases in temperature, reductions in precipitation in some regions, and increased frequency of extreme events would result in net productivity declines in major North American crops by the end of the 21st Century without adaptation, although the rate of decline varies by model and scenario, and some regions, particularly in the north, may benefit.

Human healthimpacts from extreme climate events have been observed, although climate change-related trends and attribution have not been confirmed to-date. Further climate warming in NA will impose stresses on the health sector through more severe extreme events such as heat waves and coastal storms, as well as more gradual changes in climate and CO2 levels. Human health impacts in NA from future climate extremes can be reduced by adaptation measures such as targeted and sustainable air conditioning, more effective warning and response systems, enhanced pollution controls, urban planning strategies, and resilient health infrastructure.

Observed impacts on livelihoods, economic activities, infrastructure and access to services in North American urban and rural settlements have been attributed to sea level rise, changes in temperature and precipitation, and occurrences of such extreme events as heat waves, droughts and storms. Differences in the severity of climate impacts on human settlements are strongly influenced by context-specific social and environmental factors and processes that contribute to risk, vulnerability and adaptive capacity such as hazard magnitude, populations' access to assets, built environment features and governance. Although larger urban centers would have higher adaptation capacities, future climate risks from heat waves, droughts, storms and sea level rise in cities would be enhanced by high population density, inadequate infrastructures, lack of institutional capacity and degraded natural environments.

Much of North American infrastructure is currently vulnerable to extreme weather events and, unless investments are made to strengthen them, would be more vulnerable to climate change.  

Most sectors of the North American economy have been affected by and have responded to extreme weather, including hurricanes, flooding, and intense rainfall. Despite a growing experience with reactive adaptation, there are few examples of proactive adaptation anticipating future climate change impacts, and these are largely found in sectors with longer-term decision-making, including energy and public infrastructure.

Adaptation – including through technological innovation, institutional strengthening, economic diversification, and infrastructure design – can help to reduce risks in the current climate, and to manage future risks in the face of climate change. However, adaptation limits exist.


Presenter: Paty Romero-Lankao
Date: Friday, April 4, 2014 
Source: UCARConnect

NCAR social scientist Paty Romero-Lankao served as a contributing author for the Intergovernmental Panel on Climate Change's Fifth Assessment Report. Romero-Lankao captures the essence of the IPCC Working Group II's findings from their report, "Climate Change 2014: Impacts, Adaptation, and Vulnerability." It focuses on the potential impacts of climate change and how society can try to adapt.

Romero Lankao is an interdisciplinary sociologist who studies the causes and societal impacts of climate change, especially as applied to urban areas. Her work explores the dynamics of urbanization – such as demographics, density, and urban planning – that shape urban emissions, environmental risk, and the vulnerability of populations. Her research includes examining why and how particular cities attempt to meet the challenges of reducing emissions while improving their resilience to heat waves, flooding, and other impacts.


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