Climate change poses risks for human and natural systems: Key quotes from the IPCC’s Working Group 2 report
The Intergovernmental Panel on Climate Change released a big report on the impacts of climate change yesterday. The report looked at everything from how climate change puts species and societies at risk, to what rising emissions may mean for marine life and extreme weather events.
We pick out some key quotes from the IPCC’s Working Group 2 Summary for Policymakers.
Impacts of climate change
“Human interference with the climate system is occurring, and climate change poses risks for human and natural systems.”
“In recent decades, changes in climate have caused impacts on natural and human systems on all continents and across the oceans.”
“Some risks of climate change are considerable at 1 or 2°C above preindustrial level. Global climate change risks are high to very high with global mean temperature increase of 4°C or more … and include severe and widespread impacts on unique and threatened systems, substantial species extinction, large risks to global and regional food security”
“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 countries.”
Food production & security
“All aspects of food security are potentially affected by climate change, including food access, utilization, and price stability (high confidence).”
“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 (high confidence).”
“Global temperature increases of ~4°C or more above late-20th-century levels, combined with increasing food demand, would pose large risks to food security globally and regionally (high confidence).”
Vulnerable societies
“People who are socially, economically, culturally, politically, institutionally, or otherwise marginalized are often highly especially vulnerable to climate change and also to some mitigation and adaptation climate change responses (medium evidence, high agreement).”
“Risks are unevenly distributed and are generally greater for disadvantaged people and communities are generally greatest in countries at all levels of development.”
“Many key risks constitute particular challenges for the least developed countries and vulnerable communities, given their limited ability to cope.”
Threatened ecosystems
“Some unique and threatened systems, including ecosystems and cultures, are already at risk from climate change (high confidence). The number of such systems at risk of severe consequences is higher with additional warming of around 1°C.”
“Many species and systems with limited adaptive capacity are subject to very high risks with additional warming of 2°C, particularly Arctic-sea-ice and coral-reef systems”
“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.”
Oceans
“The progressive expansion of oxygen minimum zones and anoxic “dead zones” is projected to further constrain fish habitat.”
“For medium- to high-emission scenarios… ocean acidification poses substantial risks to marine ecosystems, especially polar ecosystems and coral reefs”.
“Highly calcified mollusks, echinoderms, and reef-building corals are more sensitive than crustaceans (high confidence) and fishes (low confidence), with potentially detrimental consequences for fisheries and livelihoods”
Extreme weather
“Climate-change-related risks from extreme events, such as heat waves, extreme precipitation, and coastal flooding, are already moderate (high confidence) and high with 1°C additional warming (medium confidence). Risks associated with some types of extreme events (e.g., extreme heat) increase further at higher temperatures (high confidence).”
“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 (very high confidence).”
Human health
“Until mid-century, projected climate change will impact human health mainly by exacerbating health problems that already exist (very high confidence).”
“Local changes in temperature and rainfall have altered the distribution of some water-borne illnesses and disease vectors (medium confidence).”
“By 2100 for the high-emission scenario RCP8.5, 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 (high confidence).”
Human security & conflict
“Climate change over the 21st century is projected to increase displacement of people (medium evidence, high agreement).”
“Climate change can indirectly increase risks of violent conflicts in the form of civil war and inter-group violence by amplifying well-documented drivers of these conflicts such as poverty and economic shocks”.
“The impacts of climate change on the critical infrastructure and territorial integrity of many states are expected to influence national security policies (medium evidence, medium agreement).”
Adapting to climate change
“Adaptation is place and context specific, with no single approach for reducing risks appropriate across all settings (high confidence).”
“The relative costs of coastal adaptation vary strongly among and within regions and countries for the 21st century.”
“Some low-lying developing countries and small island states are expected to face very high impacts that, in some cases, could have associated damage and adaptation costs of several percentage points of GDP.”
Cutting emissions
“Reducing climate change can also reduce the scale of adaptation that might be required.”
“Adaptation and mitigation choices in the near-term will affect the risks of climate change throughout the 21st century (high confidence).”
“Since mitigation reduces the rate as well as the magnitude of warming, it also increases the time available for adaptation to a particular level of climate change, potentially by several decades. Delaying mitigation actions may reduce options for climate-resilient pathways in the future.”