Transcript Ecological Impacts & Adaptive Strategies

Ecological Impacts
& Adaptive Strategies
Ecosystems Defined
• “Ecosystems are communities of plants,
animals, microbes, and the physical
environment in which they exist […and
describes] plantation forests and
agricultural systems” as well
NAST (2000), Our Changing Climate, p. 24
Ecosystems Defined
• “Humans are not apart from the Earth –
they are a part of the Earth.”
• Tony’s personal philosophy
Ecosystem Impacts, Generally
• Greatest impacts are to Arctic and alpine
ecosystems, ecosystems with high levels
of endemic species, island ecosystems,
wetlands and mangrove forests (especially
those bounded by human settlements)
and South African ecosystems – in other
words, systems where the species
have nowhere left to go
Ecosystem Impacts, Generally
NAST (2000), Our Changing Climate, p. 25
Tropical Rainforest
Source:
http://www.uwsp.edu/geo/faculty/ritter/images/
biosphere/vegetation/rainforest_Congo_FAO.jpg
Source:
http://pas.byu.edu/pas100/peten_rainforest.jpg
Taiga/Boreal Forest
Source: http://www.nearctica.com/biomes/boreal/
taiga1.jpg
Source: http://www.nearctica.com/biomes/boreal/
taiga2.jpg
Tundra Biome
Source: http://www.marietta.edu/~biol/biomes/images/
tundra/alaskapipeline1.jpg
Source:
http://waynesword.palomar.edu/images/biome2b.jpg
Taiga/Tundra Ecotone
Source: http://fp.bio.utk.edu/botany120lect/Biomes/Biome01/ArealAlaskaTundra-Shanks.JPG
Ecosystem Impacts, Generally
•The Golden Toad of the Cloud Forests of Costa Rica
may be the first climate change casualty
Warren, R. (2006)
van Vliet, A., and Leemans, R. (2006)
Lanchberry, J. (2006)
(etc.)
Ecosystem Impacts, Generally
• Climate change is just one significant
threat
• It acts in concert with other human effects
– Habitat destruction (deforestation,
development…) & the resulting fragmentation
– Invasive species
– Over-hunting / fishing
– Pollution
– Etc.
NAST (2000), Our Changing Climate
(etc.)
Ecosystem Impacts, Generally
• Ecosystem impact predictions have generally
•
been too conservative
Most existing models are flawed:
– (1) they aggregate ecosystems into coarse units,
when species respond uniquely and locally;
– (2) they usually only consider mean temperature
changes and ignore extreme conditions;
– (3) they ignore transient response (and thus rates of
change) and only indicate potential final responses
van Vliet, A. and Leemans, R. (2006)
Ecosystem Impacts, Generally
• 15-40% species extinct with 2°C warming
• “Hotspots” have the most to lose
– 25 hotspots cover 1% of Earth’s landmass yet
account for 44% of plants and 35% of
animals
• 1/3 of amphibians in danger of extinction
• Ecosystems can only adapt to a rate of
change of +0.5°C / decade
Warren, R. (2006)
Stern Review (2006), p. 79
“Diversity of Species Faces 'Catastrophe’…” (2006)
“Warming link to amphibian disease” (2006)
Ecosystem Impacts, Generally
• 80% of observed changes in
•
species distributions can be
explained by climate change
There is an increased risk of
wildfire: in Indonesia,
810,000 Ha burned in the
past decade, including
100,000 Ha of Orangutan
habitat
1 Ha = 2.47 ac
van Vliet, A. and Leemans, R. (2006)
http://en.wikipedia.org/wiki/Orangutan
Ecosystem Impacts, Generally
• Observed changes: According to two
meta-studies looking at hundreds of other
studies looking at up to 1,700 species,
“87% of shifts in phenology and 81% of
range shifts were in the direction expected
from climate change”, “i.e., towards higher
latitudes or altitudes, or earlier spring
events”
Lanchberry, J. (2006), p. 144
Ecosystem Impacts, Generally
• Phenology “deals with the times of annual recurring
•
•
•
natural events like flowering, leaf unfolding, fruit
ripening, leaf coloring and fall, migration, and spawning”
– and these patterns are changing [p. 136]
In the northern hemisphere, spring is coming up to 10
days sooner and fall ending a few days later
Timing mismatches are occurring: for example some
birds are laying eggs sooner but not as soon as their
primary food source, leading to increased infant
mortality
Species have been migrating – on average – 6km
poleward per decade over the last 40 years
van Vliet, A. and Leemans, R. (2006)
Ecosystem Impacts, Generally
• Most importantly: ecosystems are affected by
•
extremes much more than they are by
averages.
“observed responses to observed changes in
weather patterns [...] seem to be directly caused
by extreme events, such as high
temperatures early in the season, warmer
and wetter winters and dry summers.” [p.
138]
van Vliet, A. and Leemans, R. (2006)
Ecosystem Impacts, Generally
• At +1°C, 10% of global ecosystems
•
•
•
•
•
transformed, losing between 2-47% of extent
At +2°C, 16% of global ecosystems
transformed, losing between 5-66% of extent
At +2-5°C, 50% probability of THC collapse
At +3°C, 50% of nature reserves cannot fulfill
their conservation objectives
At +3°C, 22% of global ecosystems
transformed, losing between 7-74% extent
At +4°C, THC collapses
Warren, R. (2006)
Climate, General Trends
• The atmosphere has warmed by 0.76°C
since pre-industrial times
• Warming has increased by an average rate
of 0.13°C / decade for the past 50 years
• Warming can be expected to increase by
0.2°C / decade over next two decades
IPCC AR4 (2007)
Climate, General Trends
Year
IS92a
A1Fl
A2
A2c
B1
B2
2020s
1.10
0.99
0.90
0.88
0.84
0.91
2050s
2.06
2.26
1.91
1.85
1.40
1.61
2080s
3.00
3.97
3.25
3.32
2.06
2.38
2.4-6.4
(4.0)
2.0-5.4
(3.4)
1.1-2.9
(1.8)
1.4-3.8
(2.4)
2090s
dT in °C from pre-industrial
2020s-2080s: Warren, R. (2006), p. 93
2090s: IPCC AR4 (2007), p. 11
Ecosystem Effects, Generally
•Mangroves in Asia could be lost at +2.4-2.8°C, as they cannot survive SLR of
45cm (SRES Scenarios A1T, A1B, and B2)
National Geographic (Feb. 2007)
Warren, R. (2006), pp. 95-97
IPCC AR4 (2007)
The Oceans: Acidifying
• Typical ocean pH is 8.1, but this varies spatially
• Ocean pH has dropped (acidified) by 0.1 since pre•
•
•
industrial times, and is decreasing at a rate of 0.015 /
decade
If atmospheric CO2 concentration reaches 700ppm,
ocean pH will decrease by 0.3; if it reaches 1000ppm,
0.5
“These geochemical changes are highly predictable” [p.
65]
CaCO3 + CO2 + H2O <--> Ca2+ + CO32- + CO2 + H2O <-> Ca2+ + 2HCO3Turley, C. (2006)
The Oceans: Acidifying
Turley, C. (2006), p. 66
The Oceans: Acidifying
Turley, C. (2006), p. 67
The Oceans: Acidifying
• Unknown effects for most marine organisms
• Form of key macronutrients (phosphorus and nitrogen)
•
•
changed in acidic environment -> eutrophication
Changed carbonate chemistry will affect calcifying
organisms such as coccolithophores, pteropods,
gastropods, foraminifera and corals
Coccolithophores play an important role in the global
carbon cycle
– Form blooms 100,000s km2
– Are a “major producer of dimethyl sulphide (DMS) which may
have a role in climate regulation via the production of cloud
condensation nuclei” [p. 67]
Turley, C. (2006)
Coccolithophore Malformations
Figs a-c: Under normal atmospheric CO2 concentration (~300 ppmv)
Figs d-e: Under enriched atmospheric CO2 (780-850 ppmv)
Source: http://www.noc.soton.ac.uk/soes/staff/tt/eh/pics/ulf.jpg
Pteropods
Source:http://www.amonline.net.au/exhibitions/beyond/images
Pteropods are tiny, free-swimming marine snails which have developed two
wing-like flaps in place of the large muscular foot of most snails.
Gastropods
Source: http://www.dnr.sc.gov/marine/sertc/images/ photo%20gallery/
Foraminifera
Source: http://www.ucmp.berkeley.edu/foram/foramshapessm.jpg
Foraminifera are a large group of amoeboid protists with fine strands of
cytoplasm that branch and merge to form a dynamic net. They typically
produce a shell, or test, which can have either one or multiple chambers, some
becoming quite elaborate in structure.
The Oceans: Coral Reefs
• “Rainforests of the oceans”,
•
•
•
providing homes for 25-33% of all
marine life
“Coral calcification rates may
decrease by 21-40% over the
period 1880-2065 in response to
atmospheric CO2 changes” [p. 68]
Recently discovered cold water
reefs may be even more sensitive
than their tropical cousins
The Great Barrier Reef has existed
for 18 million years and may die in
our lifetime
http://en.wikipedia.org/wiki/Great_Barrier_Reef
Turley, C. (2006)
“Climate Change Shattering Marine Food Chain” (2006)
The Oceans: Coral Reefs
• At +1°C, 80% of coral reefs
•
•
•
•
will die
At +1.4°C, Indian Ocean reefs
cannot survive
At +2°C, 97% of reefs will
have died, with annual
bleaching occurring at +2.3°C
The importance of extremes:
16% of reefs died in 1998
when temperatures peaked at
1-3°C above mean maximum
20% of reefs have been lost
due to climate change,
pollution, and bottom-dredging
• Coral bleaching is a vivid
sign of corals responding to
stress, primarily increased
water temperatures.
• Once bleaching begins, corals
tend to continue to bleach
even if the stressor is
removed. If the coral colony
survives, it often requires
weeks to months for the
remaining symbiont population
to reach a normal density
• Sometimes, but not always, a
fatal event
Warren, R. (2006)
Hare, B. (2006)
“Climate Change Shattering Marine Food Chain” (2006)
http://en.wikipedia.org/wiki/Coral_bleaching
The Oceans: Coral Reefs
Bleaching, disease, and spawning events
ReefBase GIS
IPCC AR4 (2007), p. 18
The Arctic
• “In the Arctic even a slight shift in temperature, raising
•
averages to above freezing, can bring about rapid and
dramatic changes in an ecosystem that is defined by
being frozen” [p. 215]
“The effect of a 2°C global warming suggests […]
greater changes in terrestrial arctic ecosystems during
the 21st century than have occurred since the end of the
last major glacial epoch” [p. 216]
– Extinction of polar bear, seal, walrus, and the Inuit culture
• Rates of change in local temperature are 0.45-0.75°C /
decade, possibly as high as 1.55°C / decade
• Changes in the Artic affect the planetary system, as
Arctic ice reflects a great deal of sunlight
Folkestad, T. (2006)
The Arctic
• At +1°C, only 53% of tundra remains stable
• At +1.5°C, onset of melting in Greenland,
•
•
leading to +0.75m SLR by 2100
At +2°C, 42% of tundra remains stable
“Arctic tundra is the main breeding habitat for
more than 20 million individual geese and
waders that over-winter in the mid-latitudes of
Europe, Asia, and North America.” [p. 217]
– Some species of birds may lose up to 50% of their
breeding habitat at +2°C
Warren, R. (2006)
Folkestad, T. (2006)
The Arctic: Taiga and Tundra
Folkestad, T. (2006), p. 217
The Arctic: Taiga
•At +4°C, we can expect a 44% loss of the taiga and a 60% loss
of the tundra
Warren, R. (2006)
http://en.wikipedia.org/wiki/Taiga
Antarctica
• Over the past 25 years, some
penguin populations have
shrunk by 33 percent in parts
of Antarctica, due to declines
in winter sea-ice habitat
• At +2°C, key molluscs will die
out, leading to severe
ecosystem disruption
• At +4°C, we can expect an
80% decline in krill, severely
affecting penguins
• At +2-4.5°C, potential
triggering of WAIS collapse,
leading to +0.75m SLR by
2100
http://en.wikipedia.org/wiki/Penguin
Africa
• At +1°C, significant loss of Karoo (S.A.), the richest floral
•
•
•
•
•
area in the world
At +2.5°C, 100% loss of Karoo and its 2,800 endemic
plants
Loss of the Fynbos, along with 80% of the plants of the
Cape Floral Kingdom (S.A.), the smallest and most
biodiverse floral kingdom in the world
African Great Lakes wetland ecosystems collapse
At +2-3°C, 5 S.A. parks lose >40% of their animals
At +3°C, Kruger National Park (S.A.) loses 2/3 of its
species
Warren, R. (2006)
Hare, B. (2006)
“Libya’s Thirst” (2006)
Africa: Karoo & Fynbos
http://www.tropicalisland.de/CPT%20Little%20Karoo%20Oudtshoorn%20Cango%
20Wildlife%20Ranch%20Cheetahland%20lion%20b.jpg
King Protea, National Flower of S.A.
http://www.wildlifesafari.info/images/fynbos_habitat.jpg
Americas
• The Mountain Pine Beetle has expanded to
•
regions of Canada in British Columbia where
previously it was “climatically unsuitable” (killing
2m Ha of ponderosa)
In the US, the milder winters are allowing Pine
Beetle populations to double yearly (for the past
6 years), such that it is devastating pine forest in
the western and northwestern states
1 Ha = 2.47 ac
van Vliet, A. and Leemans, R. (2006), p. 137
Americas
• At +1°C, glacier melt in Peru will cause
•
•
•
•
“significant problems” [pp. 95-97]
At +2°C, potential environmental refugees
from Peru [pop: 28m] as glaciers melt
Impacts on salmonid fish
At +2-3°C, maples threatened in N. America
Conversion of Amazon rainforest into
savannah, “a potentially significant […] change”
[Halpin, p. 832]
Warren, R. (2006)
Halpin, P.N. (1997)
Americas: USA
NAST (2000), Our Changing Climate, p. 28
Americas: USA
•Note that these
figures indicate
where ecosystems
would exist given
the expected climate
of the region, not
where they will exist
NAST (2000), Our Changing Climate, p. 29
Asia
• At +2°C, 50% loss of
•
•
•
•
Chinese boreal forests
50% loss of Sundarbans
(wetlands and mangrove
forest) in Bangladesh
At +2.5°C, 100% loss of
Chinese boreal forests
Mangroves might
disappear
Desertification and loss of
permafrost on Tibetan
plateau
There are approximately 700 Bengal
Tigers in the Sundarbans
http://en.wikipedia.org/wiki/Sundarbans
Warren, R. (2007)
Australia
• At +1°C, extinctions in Dryandra forest
• 50% loss of Queensland rainforest
• At +2°C, 50% loss of Kakadu wetland in
Australia
• At +2.5°C, total loss of Kakadu
• At +3°C, 50% loss of eucalyptus
• 80% loss of range of endemic butterfly
Warren, R. (2006)
Australia: Kakadu & Butterflies
http://en.wikipedia.org/wiki/Kakadu
http://www.markju.net/wildlife/thumbs/australia/butterfly01.jpg
Europe
• Already losses of alpine flora
• “Seabirds on the North Sea coast of
Britain suffered a large-scale breeding
failure in 2004”, due to a shortage of
sandeels, which fed on phytoplankton
which shifted poleward thanks to a
+1.05°C temp shift between 1977 &
2001 [Lanchbery, p. 145]
• At +3°C, alpine species near extinction
• 60% species loss in Mediterranean, as
well as high risk of fire and loss of
migratory bird habitat
• At +4°C, 38% of alpine species lose 90%
of range
North Sea
http://www.ikzmd.de/abbildungen/53_NorthSeaMap.jpg
Lanchbery, J. (2006)
Warren, R. (2006)
Burning Embers: A New Target
van Vliet, A. and Leemans, R. (2006)
Adaptations
• Adaptive ability depends on:
–
–
–
–
(1)
(2)
(3)
(4)
rate of climate change;
migratory potential of species;
competitive pressure between species;
physical (human) obstacles in the way
–
–
–
–
(1)
(2)
(3)
(4)
connective corridors;
stepping-stone nature preserves;
protected-area buffer zones;
management planning at the regional ecosystem level.
• The following are techniques that are considered to help:
• But Halpin notes that there has been little good research
on ecosystem adaptations, on which landscape elements
should be protected and why
Halpin, P.N. (1997)
Adaptations & Mitigations
• Some suggestions:
•
– Stop paving over
everything
– Bulldoze suburban
settlements near
wetlands to allow for
their expansion in
response to SLR (bear
in mind those people
will need to evacuate
anyway)
Extend the “right to life”
to all species
• B1 Emissions Scenario:
•
•
“The B1 storyline … describes a
convergent world with [a] global
population that peaks in midcentury and declines thereafter, as
in the A1 storyline, but with rapid
change in economic structures
toward a service and information
economy, with reductions in
material intensity and the
introduction of clean and resource
efficient technologies. The
emphasis is on global solutions to
economic, social and
environmental sustainability,
including improved equity, but
without additional climate
initiatives”
How can we improve upon this?
What are its flaws?
IPCC AR4 (2007)
Climate, General Trends
Year
IS92a
A1Fl
A2
A2c
B1
B2
2020s
1.10
0.99
0.90
0.88
0.84
0.91
2050s
2.06
2.26
1.91
1.85
1.40
1.61
2080s
3.00
3.97
3.25
3.32
2.06
2.38
2.4-6.4
(4.0)
2.0-5.4
(3.4)
1.1-2.9
(1.8)
1.4-3.8
(2.4)
2090s
dT in °C from pre-industrial
2020s-2080s: Warren, R. (2006), p. 93
2090s: IPCC AR4 (2007), p. 11
Reasons for Hope
• The Permian-Triassic Extinction, which occurred about
251 mya, killed about 95% of all species.
– Recovery of “normal” levels of biodiversity took about 6 million
years (of which most of that recovery occurred at the tail end, in
500 thousand years)
– During that period, fungus is likely to have been the dominant
form of life, representing nearly 100% of the fossil record
• In other words, as least we’re not as bad as a 15-20km
wide comet or asteroid; and even if we were, the Earth
will only be covered by fungus for a mere 6 million years
Eshet, Y. et al. (1995)
http://www.space.com/scienceastronomy/planetearth/extinction_permian_000907.html
http://www.space.com/scienceastronomy/planetearth/extinction_sidebar_000907.html
http://www.palaeos.com/Mesozoic/Triassic/Olenekian.html