The IPCC and Climate Change 2022
Since the Intergovernmental Panel on Climate Change (IPCC) was established in 1988 it has delivered five Assessment Reports, in addition to numerous special reports on subjects such as Emissions, Aviation, Carbon Dioxide Capture and Storage, and Global Warming. The Assessment Reports typically consist of a report from each of three working groups and a Synthesis Report. Working group I assesses topics including “greenhouse gases and aerosols in the atmosphere; temperature changes in the air, land and ocean; the hydrological cycle and changing precipitation (rain and snow) patterns; extreme weather; glaciers and ice sheets; oceans and sea level; biogeochemistry and the carbon cycle; and climate sensitivity.” Working Group II assesses “the vulnerability of socio-economic and natural systems to climate change, negative and positive consequences of climate change and options for adapting to it”. Working Group III “focuses on climate change mitigation, assessing methods for reducing greenhouse gas emissions, and removing greenhouse gases from the atmosphere” (IPCCwgs, 2022).
In February
2022 the IPCC finalized the second part of its Sixth Assessment Report, Climate
Change 2022: Impacts, Adaptation and Vulnerability (IPCCar6, 2022). The length
of the report exceeds three thousand pages, and the following discussion will
be based largely on the Summary for Policymakers (SPM). Many statements in the
SPM have assigned to them a level of confidence (very low, low, medium, high,
and very high), which are not statistical confidence levels, but are based on
two factors, a level of agreement and a degree of evidence (IPCCgn, 2010). The IPCC
Summaries for Policymakers have been “subject to detailed, line-by-line
discussion, leading to agreement among the participating IPCC member countries,
in consultation with the scientists responsible for drafting the report” (IPCCf,
2021). There are 195 member countries.
Several articles
list findings from the report which are considered to be of key importance. For
Levin, Boehm and Carter (2022) there were six main headings: “Climate impacts are
already more widespread and severe than expected; We are locked into even worse
impacts from climate change in the near-term; Risks will escalate quickly with
higher temperatures, often causing irreversible impacts of climate change; Inequity,
conflict and development challenges heighten vulnerability to climate risks; Adaptation
is crucial. Feasible solutions already exist, but more support must reach vulnerable
communities; some impacts of climate change are already too severe to adapt to.
The world needs urgent action now to address losses and damages.”
Eight
humanitarian insights from the report are described by de Perez, Suarez and van
Aalst (2022). Climate change is contributing to humanitarian crises; it has already
disrupted the lives of billions; its consequences for Humanity will get even
worse, sooner than we thought; it doesn’t act alone, and marginalisation makes its
impacts worse; everyone everywhere can adapt, within limits; funding and action
are absurdly short; responding to climate change will create new risks; and
time is short for us to choose a radically new, climate resilient future.
Writing in
The Guardian, Harvey (2022) outlined some of the report’s warnings. “3.5
billion people are highly vulnerable to climate impacts” with water shortages
and heat stress as major threats. A billion coastal dwellers will be exposed to
flooding risk by 2050, and rising temperatures and rainfall are “increasing the
spread of diseases in people, such as dengue fever, and in crops, livestock and
wildlife.” If temperature increase is kept to 1.6C by 2100, there will still be
an 8% loss of climatically suitable farmland compared to today. With continued
warming and inadequate adaptation, “183 million more people are projected to go
hungry by 2050.” Harvey regards the question of “loss and damage” as one of the
most contentious, the “impacts of the climate crisis that are too great for
countries to adapt to”, and notes the disappointment felt by many countries
after the COP26 climate summit “failed to agree a programme to issue funding to
poor countries for the loss and damage they sustain.”
The SPM has
an introduction and three main sections: Observed and Projected Impacts and
Risks; Adaptation Measures and Enabling Conditions; and Climate Resilient Development.
Extracts from each section are included in the following paragraphs.
Observed and
Projected Impacts and Risks
Since the previous
Assessment Report “the knowledge base on observed and projected impacts and
risks generated by climate hazards, exposure and vulnerability has increased.” These impacts and risks can refer to “damages,
harms, economic, and non-economic losses.” Human-induced climate change has adversely
impacted nature and people, “beyond natural climate variability.” In general “the
most vulnerable people and systems” are disproportionately affected, and there
have been “some irreversible impacts as natural and human systems are pushed
beyond their ability to adapt.” Climate change has adversely affected physical and
mental health, and in all regions “extreme heat events have resulted in human
mortality and morbidity”; in urban settings it has “caused impacts on human
health, livelihoods and key infrastructure”, with intensification of heatwaves
in cities. There have been benefits in some regions “from lower energy demand
as well as comparative advantages in agricultural markets and tourism”. Climate
change and weather
extremes contribute to humanitarian crises in areas with high vulnerability,
and are “increasingly driving displacement in all regions” particularly Small
Island States. “Vulnerability of ecosystems and people to climate change
differs substantially among and within regions” and the driving factors include
“unsustainable ocean and land use, inequity, marginalization, historical and
ongoing patterns of inequity”. The number of people living in “contexts that
are highly vulnerable to climate change” is estimated at approximately 3.3 to
3.6 billion.
Risks are
considered in two time periods, near term (2021–2040) and mid to long term
(2041–2100). If global warming reaches
1.5°C in the near-term, risk of biodiversity loss is predicted for kelp and
seagrass ecosystems, Arctic sea-ice and terrestrial ecosystems and warm-water coral
reefs. “Continued and accelerating sea level rise will encroach on coastal
settlements and infrastructure … and commit low-lying coastal ecosystems to
submergence and loss … Regional differences exist, and risks are highest where
species and people exist close to their upper thermal limits, along coastlines,
in close association with ice or seasonal rivers.” Some of these near-term
risks are unavoidable, others can be moderated.
Mid to
long-term risks include further biodiversity loss and degradation, and
transformation of ecosystems. Risks of extinction of the terrestrial species
assessed are set against temperature rise: for example 3 to 14% for global warming levels of 1.5°C,
rising to 3 to 48% at 5°C. Risks associated with “physical water availability”
and water-related hazards are also assessed for various levels of warming, and
climate change will “increasingly put pressure on food production and access,
especially in vulnerable regions, undermining food security and nutrition”. Sub-Saharan
Africa, South Asia, Central and South America and Small Islands are at
particular risk of “malnutrition and micro-nutrient deficiencies” if
temperature increases reach or exceed 2°C. Soil health and “ecosystem services
such as pollination” are threatened, and pests and diseases are likely to increase,
“undermining food productivity in many regions on land and in the ocean”. Under
all levels of warming climate-sensitive “food-borne, water-borne, and
vector-borne disease risks are projected to increase.” Coastal settlements and
infrastructure are at particular risk:
the “population
potentially exposed to a 100-year coastal flood is projected to increase by
about 20% if global mean sea level rises by 0.15 m relative to 2020 levels”.
While it is difficult to produce robust estimates, “global aggregate net
economic damages generally increase non-linearly with global warming levels”. Progressive
warming is likely to result in “involuntary migration from regions with high
exposure and low adaptive capacity”. Risks are also listed by region, under the
headings of Small islands, North America, Europe, Central and South America,
Australasia, Asia, and Africa.
Several scenarios
are described under the heading of “Complex, Compound and Cascading Risks”. Risks
can interact, “generating new sources of vulnerability to climate hazards, and
compounding overall risk”; loss of food production due to heat and drought can
be “exacerbated by heat-induced labour productivity losses”. Risks from climate
hazards can cascade across sectors and regions. For example “climate impacts to
key infrastructure are leading to losses and damages across water and food
systems, and affect economic activity, with impacts extending beyond the area
directly impacted by the climate hazard”. Effects of climate extremes can
propagate across national boundaries through “supply-chains, markets, and
natural resource flows” with consequences in the water, energy and food
sectors. Some measures intended to reduce the risks of climate change can
produce new risks: one example is the afforestation of unsuitable land which
can reduce biodiversity, water and food security; another is the deployment of
solar radiation modification, a technique which might result in overcompensating
change “at regional scales and seasonal timescales.” Transient warming above 1.5°C
may “cause release of additional greenhouse gases” and some effects could be
irreversible. Temporary overshoot could affect polar, mountain, and coastal
ecosystems, due to ice-sheet and glacier melt, and higher sea level rise.
Adaptation
Measures and Enabling Conditions
Adaptation
is at present reducing climate risks mainly by adjusting existing systems, and
“implementation depends upon the capacity and effectiveness of governance and
decision-making processes”. There has been progress in all sectors and regions,
but there is unevenness and there are gaps. Prioritising near term risk
reduction can reduce “the opportunity for transformational adaptation”. The majority of documented adaptation
addresses water-related
risks; examples are early warning systems and levees to reduce inland flooding.
It is critically important to consider climate change impacts “in the design
and planning of urban and rural settlements”, and in energy system transitions
“the most feasible adaptation options” support resilience, reliable power and
efficient water use. Some human adaptation can be furthered by addressing “financial,
governance, institutional and policy constraints” but with additional warming
adaptation limits will be reached. Maladaptive responses have been observed
which can create “lock-ins of vulnerability, exposure and risks that are
difficult and expensive to change”; inclusive and long-term planning can help
to avoid them. The requirements for adaptation in human systems and ecosystems
include “political commitment and follow-through”, clear goals and priorities,
and adequate financial resources.
Climate
Resilient Development
Worldwide climate
resilience development action is more urgent than was indicated by the previous
Assessment Report, AR5. “Comprehensive, effective, and innovative responses can
harness synergies and reduce trade-offs between adaptation and mitigation to advance
sustainable development”, but there is a “rapidly narrowing window of
opportunity” for action, which is enabled when “governments, civil society and
the private sector make inclusive
development choices that prioritise risk reduction, equity and justice”, with
integrated decision-making, finance and actions across “governance levels,
sectors and timeframes”. Global
urbanisation offers “a critical opportunity” for climate resilient development.
Urgent decision making is required “for the new built environment and
retrofitting existing urban design, infrastructure and land use.”
“Biodiversity
and ecosystem services have limited capacity to adapt to increasing global
warming levels” making protection and restoration “essential for maintaining
and enhancing the resilience of the biosphere”: analyses of a range of evidence
have suggested that this will require “effective and equitable conservation of
approximately 30% to 50% of Earth’s land, freshwater and ocean areas”.
References
de Perez,
E.C., Suarez, P., and van Aalst, M., 2022, The Science of Climate Impacts: Eight
humanitarian insights from the latest IPCC report, Climate Centre, online, accessed 25 March
2022
Harvey, F.,
2022, What is the IPCC climate change report – and what does it
say? The Guardian, Mon 28 Feb 2022, online, accessed 24 March 2022
IPCCar6,
2022, Sixth Assessment Report: Climate Change 2022: Impacts, Adaptation and
Vulnerability, online, accessed 24
March 2022
https://www.ipcc.ch/report/ar6/wg2/
IPCCf, 2021,
IPCC Fact Sheet: How does the IPCC approve reports? online, accessed 24 March
2022
https://www.ipcc.ch/site/assets/uploads/2021/07/AR6_FS_approve.pdf
IPCCgn,
2010, Guidance Note for Lead Authors of the IPCC Fifth Assessment Report on
Consistent Treatment of Uncertainties
IPCCwgs,
2022, Working Groups, online, accessed 24 March 2022
https://www.ipcc.ch/working-groups/
Levin, K., Boehm,
S., and Carter, R., 2022, “6 Big Findings from the IPCC 2022 Report on Climate
Impacts, Adaptation and Vulnerability”, February 27, 2022, World Resources
Institute, online, accessed 24 March 2022
https://www.wri.org/insights/ipcc-report-2022-climate-impacts-adaptation-vulnerability
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