Global Climate Change
David Karowe
Department of Biological Sciences
Western Michigan University
Earth’s climate has always been changing
Over the past 800,000 years:
~ 100,000 year climate cycles, due to cyclic changes in
amount of incoming solar radiation
1
Since 1900, Earth has warmed by ~ 0.8o C
Temperature Change (oC)
10 warmest years in history: 2002-2010, 1998*
- warmest year: 2010
- rate of waming is 10-100 times faster
than in at least the last 800,000 years
Temperature difference relative to 1950-1980
http://data.giss.nasa.gov/gistemp/animations/
2
Can climate change be due to “natural variation”?
Solar Irradiance
For the last 30 years, solar irradiance has been
decreasing
Since 1900, natural factors would have caused
a slight cooling of Earth
3
Bottom line: At least 95% of global warming
is due to human activities
Fossil fuel use (~80%)
Deforestation (~20%)
85% of U.S. energy comes from fossil fuels
4
Size proportional to population
Size proportional to national CO2 emissions
Midwest would be 4th highest emitting country
5
U.S. emits the most carbon per person
On average, CO2 stays in the atmosphere for ~100 years
In just the last 150 years, atmospheric CO2
increased from 280 to >390 parts per million (ppm)
6
Temperature Change (oC)
CO2 increase is the main cause of global warming
What has happened over the last 50 years?
Arctic summer sea ice has decreased by ~40%
- likely will disappear by 2100
- very strong positive feedback (albedo effect)
7
Glaciers have been melting worldwide
e.g. Peruvian glacier Qori Kalis
1978
2000
Greenland is melting and Antarctica is shattering
8
Permafrost has been melting
- CO2 and methane from decomposition enter
atmosphere (positive feedback)
Severe rainstorms have become more common
- 50% increase in southwest Michigan since 1948
9
Flooding has increased worldwide
Droughts have also increased worldwide
10
2011 was Michigan’s 3rd wettest spring on record
As a result, Michigan experienced flooding this spring
11
And there was extensive flooding along Mississippi
Tunica, Mississippi
But by late July, 51% of MI was “abnormally dry”
12
Much of the U.S. had an unusually warm summer
In late September, 43% of U.S. was in drought
September 27, 2011
South central states experienced “Exceptional Drought”
13
Right now, 58% of U.S. is in drought
September
January 31,
27,2012
2011
What does the future hold?
14
Climate change is very likely to accelerate
Earth is expected to warm by at least 2-4o C by 2100
“Business
as usual”
4o
2o
Alternate
energy
sources
Will a 4o temperature rise matter?
When Earth was 5o cooler:
15
Severe rainstorms will continue to increase
In the future, most summers are likely to be hotter
than any experienced thus far
16
In the future, most summers are likely to be hotter
than any experienced thus far
Much of the world is likely to experience much more
frequent and stronger droughts
ex
ce
ex ptio
tre na
se me l
v
m ere
od
e
m rat
ild e
dr
ou
gh
t
1950-1959
Palmer Drought Severity Index (PDSI)
17
Much of the world is likely to experience much more
frequent and stronger droughts
2000-2009
1950-1959
Palmer Drought Severity Index (PDSI)
Much of the world is likely to experience much more
frequent and stronger droughts
2060-2069
1950-1959
2000-2009
Palmer Drought Severity Index (PDSI)
18
By 2100, many species are predicted to experience
“disappearing climates” and/or “novel climates”
disappearing
Low
novel
Moderate
High
Probability
How are plants and animals likely to be affected by
future climate change?
19
Overall, tree species richness is predicted to decline
substantially throughout the U.S. by 2100
Current
2100
In Michigan, sugar maple is predicted to decline
by >60% by 2100 under “Business as Usual”
Future Low
Current
Future High
20
African mammals are likely to be adversely affected
Of 227 species, 20-40% are predicted to be extinct by
2080 due to climate change
Most Western Hemisphere amphibian species are
predicted to be adversely affected by climate change
37% of 413 species are
predicted to lose
>90% of their range
area of
greatest
vulnerability
21
Birds in high northern latitudes are particularly
vulnerable to climate change
White-winged
Crossbill
Eurasian
Dotterel
27 species lose, on
average, 74-84% of
suitable habitat by 2080
Possible loss of all coral reefs with 3o rise
and >650 ppm CO2
22
Globally, if we allow Earth to warm by 3o C,
20-50% of species may be committed to extinction
This is probably the worst time in Earth’s history for
species to track climate change via dispersal
- because humans have fragmented landscapes
23
Humans have impacted ~75% of Earth’s land surface
(red = impacted)
In Michigan, many barriers to dispersal exist
(images courtesy of August Froehlich)
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How is climate change likely to affect human health?
1. Increased heat stress and decreased cold stress
2. Increased disease (e.g. malaria, dengue)
3. Reduced air quality (e.g. higher ozone)
4. Increased malnutrition
5. Increased conflict
By 2100 in Europe, every other summer could be like
2003, when a heat wave killed up to 80,000 people
2003
1900
2100
Year
25
Michigan will experience many more days over 90o F
Climate change is likely to cause an increase in
several vector-borne diseases
e.g. malaria
1,000,000 deaths annually
Anopheles
26
Most studies predict increase in malaria, but change
depends on climate scenario
+2o C
+10% summer rain
- 10% winter rain
+4o C
+20% summer rain
- 20% winter rain
Climate-induced increases in tropospheric ozone is
predicted to cause ~2 million deaths by 2050
Annual deaths due to O3 above pre-industrial level
- health costs estimated at $580 billion per year
27
By 2030, most of the important crops in India and
Pakistan are predicted to have reduced yields
- 30% of world’s
malnourished people
What are the biggest climate change effects on
human health?
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Climate change is predicted to increase civil wars in
six African regions by 5-10% by 2030
- overall increase
in sub-Saharan
Africa of about
about 50%
Developed countries are causing the problem, but
developing countries experience most health costs
Countries proportional to
CO2 emissions (1950-2000)
Countries proportional to
climate-sensitive health effects
29
Emissions reductions need to be rapid and large
- 80% reduction by 2050 to avoid worst scenarios
Urgent need for alternate energy sources
solar
wind
Wind power could supply 16 times current U.S.
electricity demand using only onshore turbines
- Michigan can supply 12 times our current use
30
Concentrating Solar Power (CSP) is very promising
Central tower
Parabolic trough
A CSP solar array 100 x 100 miles could provide
all of U.S. electricity needs today
- excess energy captured during the day could be stored
as heat and used to produce electricity at night
31
A small portion of the Sahara desert could supply all
of Europe’s electricity (and the world’s)
Worst case scenario:
32