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IPCC Synthesis Report
Part II - Habiba Gitay
• Climate change: observed and
projected–changes in the mean state,
variability and extreme events
• Observed and projected impacts of
climate change on ecological systems,
socio-economic sectors (including
human health), and approaches to
adapt to climate change
Human activities have changed the composition
of the atmosphere since the pre- industrial era
Atmosphere
3.3
This is the
“greenhouse” problem
Humans
are
perturbing
the carbon
cycle
The KP seeks to reduce
total emissions by about 0.2
750
62.3
60
6.3
16,000
1.6
500 Plants
Soil
Driven by
fossil fuel emissions
92.3
2000
Estimated Fossil
Deposits
About
90
…and land clearing
Oceans
39,000
Units
Gt C for stores &
Gt C y-1 for fluxes
The oceans and land vegetation are currently
taking up 4.6 Gt C per year
The Land and Oceans have warmed
Precipitation patterns have changed
The frequency, persistence and magnitude of ElNino events have increased in the last 20 years
El Niño years
La Niña years
The El-Nino phenomena leads to floods and droughts throughout the
tropics and subtropics
Sea Levels have risen
Observed regional changes in temperature have
been associated with observed changes in physical
and biological systems
Examples include:
• non-polar glacier retreat
• reduction in Arctic sea ice extent and thickness in
summer
• earlier flowering and longer growing and breeding
season for plants and animals in the N.H.
• poleward and upward (altitudinal) migration of
plants, birds, fish and insects; earlier spring
migration and later departure of birds in the N.H.
• increased incidence of coral bleaching
Weather-related economic damages have
increased
Global mean surface temperatures have increased
Most of the observed warming in the past 50
years is attributable to human activities
Greenhouse gas emissions and concentrations,
temperature and sea level are projected to change
Global mean surface temperature is projected to
increase during the 21st century
Land areas are projected to warm more than the
oceans with the greatest warming at high latitudes
Annual mean temperature change, 2071 to 2100
relative to 1990: Global Average in 2085 = 3.1oC
Some areas are projected to become wetter,
others drier with an overall increase projected
Annual mean precipitation change: 2071 to 2100 Relative to 1990
Mean sea level is projected to rise by 0.09 to
0.88m by 2100, but with significant regional
variations
Extreme Weather Events are Projected to Increase
Projected changes during the 21st
century
Examples of impacts
• Higher maximum temperatures; • Increased mortality in old people
more hot days and heatwaves
in urban areas
over nearly all land areas (very • Damage to crops
likely)
• Heat stress on livestock
• Higher minimum temperatures; • Extended range of pests and
fewer cold days frost days and
diseases
cold spells over nearly all land • Loss of some crop/fruit
areas (very likely)
slides, mudslides, damage to
• more intense precipitation events • Land
property and increased insurance
over many areas (very likely)
costs
• increased summer drying over • Reduced rangeland productivity,
most mid-latitude continental
increased wildfires, decreased
interiors and associated risk of
hydropower
drought (likely)
• increase in tropical cyclone peak • Damage to various ecological and
socioeconomic systems
wind intensity, mean and peak
precipitation intensities (likely)
More adverse than beneficial impacts on biological
and socioeconomic systems are projected
Increased water availability in some water-scarce
regions, and decreased water availability in many
water scarce regions
Initially increased agricultural productivity in some
mid-latitude regions & reduction in the tropics and
sub-tropics even with warming of a few degrees
2020s
2050s
2080s
Significant disruptions of ecosystems from
disturbances such as fire, drought, pest
infestation and invasion of species
Changes in the productivity and
composition of ecological systems, with
coral reefs and boreal forests being most
vulnerable
Branching coral
Brain coral
coral bleaching events are expected to increase
Ecological systems have many interacting
non-linear processes and are thus subject
to abrupt changes and threshold effects
arising from relatively small changes in
driving variables, such as climate.
For example:
Temperature increase beyond a threshold,
which varies by crop and variety, can
affect key development stages of some
crops and result in severe losses in crop
yields.
Increased risk of floods, potentially displacing tens of
millions of people, due to sea level rise and heavy
rainfall events, especially in Small Island States and lowlying deltaic areas.
Bangladesh is projected to lose about 17% of its land area with a
sea level rise of one meter - very difficult to adapt due to lack of
adaptive capacity
projected
present
Effect on human health…
Reduced winter mortality in mid- and highlatitudes
Increased incidence of heat stress mortality,
and the number of people exposed to vectorborne diseases, such as malaria and dengue
and water-borne diseases such as cholera,
especially in the tropics and sub-tropics
Developing countries are the most vulnerable to
climate change
• Impacts are worse - already more flood and drought prone
and a large share of the economy is in climate sensitive
sectors
• Lower capacity to adapt because of a lack of financial,
institutional and technological capacity and access to
knowledge
• Climate change is likely to impact disproportionately
upon the poorest countries and the poorest persons
within countries, exacerbating inequities in health status
and access to adequate food, clean water and other
resources.
• Net market sector effects are expected to be negative in
most developing countries
Adaptation has the potential to reduce adverse
effects of climate change and can often produce
immediate ancillary benefits, but cannot prevent all
damages
• Numerous adaptation options have been
identified that can reduce adverse and enhance
beneficial impacts of climate change, but will incur
costs
• Greater and more rapid climate change would
pose greater challenges for adaptation