Greenpeace Summary of IPCC WGII Impacts
Report Summary for Policy Makers
Bill Hare and Kitsy McMullen,
Climate change is already having an impact
IPCC Working Group II has found that warming in the last few decades is
already having an effect on natural systems:
“Thus, from the collective evidence there is high confidence that recent
regional changes in temperature have had discernible impacts on many
physical and biological systems".
This finding follows from the recent findings of the IPCC Working Group I on the
Science of Climate Change that:
“There is new and stronger evidence that most of the observed warming
over the last 50 years is attributable to human activities.”
Potential for Large Scale and Irreversible Impacts
The report finds that that greenhouse gas increases over the next century could
trigger large scale and irreversible impacts.
These events may not be likely to occur in the next century but there is a
significant likelihood that they could be triggered by human activities in the next
100 years. Amongst these risks are:
The slowing down or stopping of the ocean’s thermohaline circulation.
Melting of the Greenland and West Antarctic Ice Sheets, which could lead
to up to 3 metres of sea level rise each over the next 1000 years and
“submerge many small islands and inundate extensive coastal areas.”
The melting of the ice sheets couldbe triggered by human induced
warming within the next century. In relation to the Greenland Ice Sheet,
IPCC Working Group I Summary for Policy Makers found that:
“Climate models indicate that the local warming over Greenland is likely to
be 1 to 3 times the global average. Ice sheet models project that a local
warming of larger than 3ºC, if sustained for millennia, would lead to
virtually a complete melting of the Greenland ice sheet with a resulting
sea level rise of about 7 metres. A local warming of 5.5ºC, if sustained for
1000 years, would be likely to result in a contribution from Greenland of
about 3 metres to sea level rise.
On the West Antarctic Ice Sheet the WGI report found that:
“Current ice dynamic models suggest that the West Antarctic ice sheet
could contribute up to 3 metres to sea level rise over the next 1000 years,
but such results are strongly dependent on model assumptions regarding
climate change scenarios, ice dynamics and other factors.”
Acceleration of global warming caused by releases of carbon to the
atmosphere from forest disturbance which is itself caused by climate
Releases of terrestrial carbon caused by the melting permafrost and
releases of methane, a powerful greenhouse gas, from the decomposition
of hydrates under coastal sediments on the sea bed “would further
increase greenhouse gas concentrations and amplify climate change”.
The timing of the triggering of these events are uncertain but their likelihood
increases with the rate, magnitude and duration of climate change.
Developing Countries most at risk
The report finds that developing countries are most at risk from climate change.
Global increases in temperature would produce net economic losses in many
developing countries for all magnitudes of warming and these losses would be
greater the higher the warming.
"The effects of climate change are expected to be greatest in developing
countries in terms of loss of life and relative effects on investment and the
economy. For example, the relative percentage damages to GDP from climate
extremes have been substantially greater in developing countries than in
Another finding is that: “The projected distribution of economic impacts is such
that it would increase the disparity in well-being between developed countries
and developing countries, with disparity growing for higher projected
temperature increases (medium confidence).”
There was a long discussion at the Plenary on Paragraph 17 of the Draft SPM
over the issue of whether or not it could be said that developed countries could
benefit from a small amount of warming. Paragraph 17 of the Draft SPM stated:
(I 7) Nevertheless, the published estimates indicate that increases in
global mean temperature would produce economic losses in many
developing countries for all magnitudes of warming studied, and that the
losses would be greater in magnitude the higher the level of warming
(medium confidence). In many developed countries, economic gains are
projected for global mean temperature increases up to roughly 2oC
(medium confidence). Mixed or neutral net effects are projected in
developed countries for temperature increases in the approximate range
of 2 to 3oC, and losses for larger temperature increases (medium
confidence). The projected distribution of economic impacts is such that it
would increase the disparity in well being between developed countries
and developing countries, with the disparity growing with higher
temperatures (see Figure SPM-1). The more damaging impacts
estimated for developing countries reflects, in part, their lesser adaptive
capacity relative to developed countries, exposure to more adverse water
runoff changes for many of these countries, and present day
temperatures in the tropics and subtropics that are already near the
maximum tolerances of some crops. [7.2.4]
After substantial discussion and cross-checking with the literature reported in
the underlying Chapters this finding was significantly re-cast both in its
conclusions and in the level of confidence attached to this:
“Not with standing the limitations expressed above, based on a few
published estimates, increases in global mean temperatures would
produce net economic losses in many developing countries for all
magnitudes of warming studied (low confidence 6 ), and losses would be
greater in magnitude the higher the level of warming (medium
confidence'). In contrast an increase in global mean temperature of up to
a few degrees C would produce a mixture of economic gains and losses
in developed countries (low confidence 6), with economic losses for
larger temperature increases (medium confidence 6). The projected
distribution of economic impacts is such that it would increase the
disparity in well-being between developed countries and developing
countries, with disparity growing for higher projected temperature
increases (medium confidence'). The more damaging impacts estimated
for developing countries reflects, in part their lesser adaptive capacity
relative to developed countries. [7.2.3]”
The final emphasis on the mixture of economic losses and gains reflected a
feeling that presenting net aggregate figures was misleading as it did not say
who would benefit and who would lose. From the studies cited it was clear than
even for low levels of warming there were developed countries that would suffer
net losses and within countries significant sectors would lose whilst others
gained. Similarly the level of confidence was downgraded after review of the
studies underlying the draft
More people projected to be harmed than benefited even for small
"More people are projected to be harmed than benefited by climate change,
even for global mean temperature increases of less than a few degrees."
Ecosystems and species at risk
The report finds that many natural systems are at risk. These include glaciers,
polar and alpine ecosystems, boreal and tropical forests, coral reefs and atolls,
mangrove and “biodiversity hot spots”.
Extensive Regional Impacts Identified
The impacts of climate change threaten large populations of Africa already
struggling for sustainable development.
“Grain yields are projected to decrease for many scenarios, diminishing food
security, particularly in small food-importing countries (medium-high
In a region already facing the effects of AIDS and malnutrition, climate change
will foster the expansion of a host of infectious diseases.
“Extension of ranges of infectious disease vectors would adversely affect
human health in Africa (medium confidence).”
Floods, famine, and refugee migrations are very likely as climate change tips
the balance in overburdened regions of the African continent.
“Increases in droughts, floods, and other extreme events would add to stresses
on water resources, food security, human health, and infrastructures, and would
constrain development in Africa (high confidence).”
As climate change grips Africa and vital ecosystems wither, some of the richest
biodiversity on Earth is likely to disappear.
“Significant extinctions of plant and animal species are projected and would
impact rural livelihoods, tourism, and genetic
resources (medium confidence).”
Climate change is already being experienced across the Asian continent
“Extreme events have increased in temperate and tropical Asia, including
floods, droughts, forest fires, and tropical cyclones (high confidence).”
Climate change is likely to bring disruption and instability to millions of people in
“Decreases in agricultural productivity and aquaculture due to thermal and
water stress, sea level-rise, floods and droughts, and tropical cyclones would
diminish food security in many countries of arid, tropical, and temperate Asia;
agriculture would expand and increase in productivity in northern areas
In the most densely populated regions of the world, climate change is likely to
intensify threats from infectious disease.
“Human health would be threatened by possible increased exposure to vector-
borne infectious diseases and heat stress in parts of Asia (medium
Mega-cities and densely populated areas along the Pacific and Indian Ocean
coastlines are caught between the threats of sea level rise and river flooding
from increased upstream precipitation.
“Sea level rise and an increase in intensity of tropical cyclones would displace
tens of millions of people in low- lying coastal areas of temperate and tropical
Asia; increased intensity of rainfall would increase flood risks in temperate and
tropical Asia (high confidence)”.
The combined effects of accelerating climate change and land-use pressures
are fragmenting and likely to significantly damage Asian ecosystems that
comprise some of the richest biodiversity on Earth.
“Climate change would exacerbate threats to biodiversity due to land-use and
land-cover change and population pressure in Asia (medium confidence). Sea
level rise would put ecological security at risk, including mangroves and coral
reefs (high confidence).”
The Executive Summary of the Chapter on Asia reports that “Many species of
mammals and birds could be exterminated as a result of the synergistic effects
of climate change and habitat fragmentation.”
Australia and New Zealand
Despite the hopes that climate change will be a help for some crops in Australia
and New Zealand, any short-term gains for some crops in some regions are
likely to be overwhelmed by other regional losses and long term damages.
“The net impact on some temperate crops of climate and CO2 changes may
initially be beneficial, but this balance is expected to become negative for some
areas and crops with further climate change (medium confidence).”
Droughts and fires will be even more common and water more valuable as
great portions of Australia dry up.
“Water is likely to be a key issue (high confidence) due to projected drying
trends over much of the region and change to a more El Nino-like average
Threats from extreme events are likely to change the lives of many Australians.
“Increases in the intensity of heavy rains and tropical cyclones (medium
confidence), and region-specific changes in the frequency of tropical cyclones,
would alter the risks to life, property, and ecosystems from flooding, storm
surges, and wind damage.”
The unique biological evolutionary line that has evolved in Australia and New
Zealand over millions of years, as well as some of the richest biodiversity on
Earth could be devastated by climate change.
“Some species with restricted climatic niches and which are unable to migrate
due to fragmentation of the landscape, soil differences, or topography could
become endangered or extinct (high confidence). Australian ecosystems that
are particularly vulnerable to climate change include coral reefs, arid and semi-
arid habitats in southwest and inland Australia and Australian alpine systems.
Freshwater wetlands in coastal zones in both Australia and New Zealand are
vulnerable, and some New Zealand ecosystems are vulnerable to accelerated
invasion by weeds.”
Glaciers and distribution of permafrost are sensitive indicators of climate
change. In Europe they are both shrinking at na unprecedented rate.
“Half of alpine glaciers and large permafrost areas could disappear by the end
of the 21st century (medium confidence).”
Expected flood patterns will place large portions of Europe at high risk.
“River flood hazard will increase across much of Europe (medium-high
confidence); in coastal areas, the risk of flooding, erosion, and wetland loss will
increase substantially with implications for human settlement, industry, tourism,
agriculture, and coastal natural habitats.”
Many Alpine ecosystems are very likely to disappear, along with vast tracts of
precious wildlife habitat.
“Upward and northward shift of biotic zones will take place. Loss of important
habitats (wetlands, tundra, isolated habitats) would threaten some species (high
Glaciers are shrinking in Latin America also, where they supply the water
necessary for agriculture and energy production as well as residential and
“Loss and retreat of glaciers would adversely impact runoff and water supply in
areas where glacier melt is an important water source (high confidence).”
In parts of Latin America, there will be increasing frequency of damaging
“Floods and droughts would become more frequent (high confidence) with
floods increasing sediment loads and degrade water supply in some areas.”
In Central and equatorial America, the devastation of tropical cyclones could get
“Increases in intensity of tropical cyclones would alter the risks to life, property,
and ecosystems from heavy rain, flooding, storm surges, and wind damages. “
Food security could become a serious problem for many countries in Latin
“Yields of important crops are projected to decrease in many locations in Latin
America even when the effects of CO2 are taken into account; subsistence
farming in some regions of Latin America could be threatened (high
Latin American problems with infectious diseases that thrive in a warming world
could be exacerbated.
“The geographical distribution of vector-borne infectious diseases would expand
poleward and to higher elevations, and exposures to diseases such as malaria,
dengue fever, and cholera will increase (medium confidence).”
In Latin America, valuable ecosystem resources will disappear, as already
threatened biodiversity hotspots get hotter.
“The rate of biodiversity loss would increase (high confidence).”
Climate change is likely to destroy ecosystems that define the North American
“Unique natural ecosystems such as prairie wetlands, alpine tundra, and cold
water ecosystems will be at risk and effective adaptation is unlikely (medium
Large expanses of the North American Atlantic coastal regions are very likely to
“Sea-level rise would result in enhanced coastal erosion, coastal flooding, loss
of coastal wetlands, and increased risk from storm surges, particularly in Florida
and much of the US Atlantic coast (high confidence).”
Insurance companies and government disaster relief agencies in North America
are faced with increasing demands from victims of weather events and are
unprepared for projected threats.
“Weather-related insured losses and public sector disaster relief payments in
North America have been increasing; insurance sector planning has not yet
systematically included climate change information, so there is potential for
surprise (high confidence).”
As North America copes with threats from unusual weather, risk from climate
change induced health problems is likely to increase.
“Vector-borne diseases—including malaria, dengue fever, and Lyme disease—
may expand their ranges in North America; exacerbated air quality and heat
stress morbidity and mortality would occur (medium confidence); socioeconomic
factors and public health measures would play a large role in determining the
incidence and extent of health effects.”
Rising temperatures in polar regions are already causing problems for
traditional communities and priceless ecosystems.
“Natural systems in polar regions are highly vulnerable to climate change and
current ecosystems have low adaptive capacity; technologically developed
communities are likely to adapt readily to climate change but some indigenous
communities, in which traditional lifestyles are followed, have little capacity and
few options for adaptation.”
Polar regions are already warming at alarming rates and many of their
ecosystems cannot survive the expected rates of further warming.
“Climate change in polar regions is expected to be among the largest and most
rapid of any region on the Earth, and will cause major physical, ecological,
sociological, and economic impacts especially in the Arctic, Antarctic Peninsula,
and Southern Ocean (high confidence).”
“Changes in climate that have already taken place are manifested in the
decrease in extent and thickness of Arctic sea ice, permafrost thawing, coastal
erosion, changes in ice sheets and ice shelves, and altered distribution and
abundance of species in the Polar regions (high confidence).”
Small Island States
The effects of sea level rise will be influencing, if not dominating, the
socioeconomic reality in many small island states from now on.
“The projected sea level rise of 5mm per year for the next 100 years will cause
enhanced coastal erosion, loss of land and property, dislocation of people,
increased risk from storm surges, reduced resilience of coastal ecosystems,
saltwater intrusions into freshwater resources, and high resource costs to
respond to and adapt to these changes (high confidence)”.
Fresh water will become even more crucial to small islands with climate change.
“Islands with very limited water supplies are highly vulnerable to the impacts of
climate change on the water balance (high confidence).
Current threats to the rich and unique coastal ecosystems of small islands are
exacerbated by the increasing rates of climate change.
“Coral reefs will be negatively affected by bleaching and by reduced calcification
rates due to higher carbon dioxide levels (medium confidence), mangrove, sea
grass beds, other coastal ecosystems and the associated biodiversity would be
adversely affected by rising temperatures and accelerated sea level rise
The reef fisheries that support populations on small island states are severely
threatened by expected weakening and damage to coastal ecosystems.
“Declines in coastal ecosystems would negatively impact reef fish and threaten
reef fisheries, those who earn their livelihoods from reef fisheries, and those
who rely on the fisheries as a significant food source (medium confidence)”.
Agricultural limitations on small islands will be worsened by the precipitation
variability and sea level rise resulting from climate change.
“Limited arable land and soil salinization makes agriculture of Small Island
States, both for domestic food production and cash crop exports, highly
vulnerable to climate change (high confidence).”
The socioeconomic repercussions of climate change threaten small islands’
hopes of ecotourism and sustainable development.
“Tourism, an important source of income and foreign exchange for many
islands, will face severe disruption from climate
change and sea level rise (high confidence).”
BACKGROUND TO IPCC WORKING GROUP II REPORT
ON IMPACTS OF CLIMATE CHANGE
Representatives met in Geneva to negotiate and approve the Summary for
Policymakers of the IPCC Third Assessment Report Working Group II on
Climate Change Impacts, Adaptation, and Vulnerability.
The mandate of Working Group II is to:
“…assess the scientific, technical, environmental, economic and social aspects
of the vulnerability (sensitivity and adaptability) to climate change of, and the
negative and positive (impacts) for, ecological systems, socio-economic sectors
and human health, with an emphasis on sectoral and cross-sectoral issues.”
The report builds upon past assessment reports of the IPCC, including the
conclusions from the Second Assessment Report in 1995 with a strong
emphasis on regional impacts.
Human activities are projected to cause average global temperatures to warm
1.4 to 5.8ºC by 2100 relative to the 1990 temperature average. This warming
will vary by region and within regions the effects will be accompanied by
changes in precipitation patterns and in the frequency and intensity of extreme
climate events. The Working Group II assessment states that the available
literature on climate impacts does not investigate the impacts associated with
the upper range of increased average temperatures. Therefore impacts from the
higher range of warming estimates are not represented in this report.
Threats to natural and human systems
The report finds that climate change presents are threat to most natural
systems. Those natural systems threatened include glaciers, coral reefs,
mangroves, arctic ecosystems, alpine ecosystems, prairie wetlands, native
grasslands, and biodiversity “hotspots”. Climate change will increase existing
risks of species extinction and biodiversity loss in ecosystems at every latitude
and in each region. The level of damage will increase with the magnitude and
rate of global warming.
Threats to human systems, beyond the loss of natural ecosystems, derive from
threats to water resources, agriculture, forestry, health, settlements, energy,
industry, and financial services. Vulnerability of particular human populations is
determined by degree of the nature of the threat, sensitivity and ability to adapt-
- characteristics that depend on geographic location and development level of
social, economic and environmental conditions. Tens of millions of people living
in low lying coastal areas face the risk of having to move due to flooding.
Changes already underway
Observed 20th century climate changes have already affected physical
systems. Examples include shrinkage of glaciers, thawing of permafrost, later
freezing and earlier breakup of ice on rivers and lakes. Biological systems also
appear to be responding through the lengthening of growing seasons, animal
range shifts to higher altitudes and latitudes, declines of some animal
populations, and earlier tree flowering, insect emergence, and bird egg laying.
Associations between these physical and biological phenomena and changes in
regional climate have been documented in aquatic, terrestrial, and marine
environments on all continents.
Preliminary indications that social and economic systems are affected by
regional climate changes in the 20th century, such as increased damages from
flooding and windstorms, are difficult to distinguish from coincident or alternative
explanations (such as population increase or upstream deforestation).
Threats from extremes
While a change in average temperatures or precipitation can have significant
impacts, the changes in extremes would likely impose the greatest dangers.
The report outlines the following threats:
Increased frequency of heat waves will increase crop and livestock
losses, frequency of wildfires, wildlife mortality, energy demand for
cooling, and human deaths and illness from heat stress and air pollution.
Decreased frequency of cold waves and fewer frost days will extend the
range of some pests and disease vectors while reducing losses due to
Increased frequency of high intensity rainfall will increase flood (and flash
flood) risk, with consequent property damage, soil erosion, flushed
pollutants, health threats, and deaths.
More frequent drought in mid-latitude continental interiors will increase
agricultural losses, threaten terrestrial and aquatic ecosystems, reduce
quality and availability of water with consequent health effects, and
promote land subsidence.
Increased intensity and frequency of tropical cyclones will threaten
property, coastal stability, ecosystems, health, and life.
Any increase in intensity and frequency of extreme climate events will
increase demands on already overburdened public and private financial
mechanisms to cover weather related losses.
Potential for large scale abrupt irreversible changes
The most troubling research considers the possibility of irreversible, large scale,
and abrupt effects triggered by human induced climate change. Large scale
possibilities include the triggering of changes in the thermohaline circulation in
the North Atlantic which could in coming centuries n plunging Europe into the
climate regime experienced by Labrador. The release of greenhouse gases
from disturbed permafrost or coastal methane hydrate deposits that would
accelerate climate change.
Vulnerability of the poorest
Those with the least resources have the least ability to adapt and will be the
most damaged by climate change. Increase in global mean temperatures will
produce net economic losses in many developing countries for all magnitudes
of warming, and the condition is most extreme among the poorest people in
The accumulated body of knowledge confirms the existence of substantial
vulnerabilities to the climate changes projected for this century, particularly for
poor populations, populations in coastal areas, and natural systems already
under stress. The SPM of Working Group II calls for further research to quantify
sensitivity and vulnerability of natural and human systems; to identify thresholds
of catastrophic and irreversible changes; to identify the dynamic response of
systems to multiple stresses; to predict adaptability; to measure impacts; and to
develop integrated assessments of climate change impacts.