Human-Induced Climate Change: From Quantum Mechanics to Politics
Chicago Climate Change Forum Northwestern University 22 April 2006
Michael Schlesinger
Climate Research Group Department of Atmospheric Sciences University of Illinois at Urbana-Champaign
Outline
• Climate Change Primer • Causes of the Observed Warming • Projections of Climate Changes and Their Impacts • Abrupt Climate Change – Shutdown of the Atlantic Thermohaline Circulation • Movie: Renew US
Composition of the Earth’s Atmosphere
Water vapor 0.2% Carbon Dioxide 0.03%
Oxygen 21%
Nitrogen 78%
Temperature of the Earth
2 4 2 4re Te 1 re S 0
1 S0 1/4 Te 255K 18 o C 0o F 4 But, Ts 288K 15o C 59 o F
•
Absorption and Emission of Radiation by Molecules
Molecules absorb and emit the longwave radiation emitted by the earth’s surface via changes in the quantum state of: (1) vibrations of their atoms, and (2) rotations of the entire molecule. O O But, for the changes in quantum state to occur, the molecule must have a dipole moment, that is, its center of mass must not be co-located with its center of electronic charge. Thus the molecule must not be symmetric. N2 has 2 N atoms and O2 has 2 O atoms. This symmetry means there is no dipole moment. Thus these predominant gases in the earth’s atmosphere are transparent to longwave radiation. It is as if they did not exist at all!
• •
•
Absorption and Emission of Radiation by Molecules
H2O and CO2 each have 3 non-identical atoms. H2O has a permanent dipole moment because its atoms are not in a straight line.
O
O C O
H
H
Although the atoms in CO2 are in a straight line, an asymmetric vibration of these atoms induces a dipole moment. Thus these two minor gases in the earth’s atmosphere absorb longwave radiation emitted by the earth’s surface. This is why Ts = Te + 33oC. This is an amazing consequence of quantum mechanics. Is is as if the tail wagged the dog!
Greenhouse Effect on Planets
600
Surface temperature minus radiative o C) equilibrium temperature (
520 500 400 300 200 100 0 4 Mars 33 Earth Venus
Outline
• Climate Change Primer • Causes of Observed Warming • Projections of Climate Changes and Their Impacts • Abrupt Climate Change – Shutdown of the Atlantic Thermohaline Circulation • Movie: Renew US
Causes of Observed Warming
150 (A) 1856–1990
Contribution to ²T (%)
100 50 0 -50
Anthro
Volcano
Sun
Residual
Outline
• Climate Change Primer • Causes of the Observed Warming • Projections of Climate Changes and Their Impacts • Abrupt Climate Change – Shutdown of the Atlantic Thermohaline Circulation
Market Impacts of the A2 Scenario in 2100 for ∆T2x=2.5oC
Outline
• Climate Change Primer • Causes of the Observed Warming • Projections of Climate Changes and Their Impacts • Abrupt Climate Change – Shutdown of the Atlantic Thermohaline Circulation • Movie: Renew US
Simulated THC UIUC AOGCM Control Run
The Ocean Currents (simulation)
Upper ocean (0~1000 m) Deep ocean (1000~3000m)
Simulated THC, Control Run
30o N 50o N
N. America
Europe
N. America
Europe
The importance of the THC in the present climate
NCAR/NCEP ECMWF 1.6 1.4
PW (10 Watts )
1.2 1 0.8 0.6 0.4 0.2 0 -90
The Atlantic Ocean
15
-60
-30
0 Latitude
30
60
90
Trenberth et al. 2001
The importance of the THC in the present climate
Carnot Engine Efficiency = 100*(1 – Cold Temp/Hot Temp) = 100*(1 –1.6 277/293) = 5.5%
1.4
PW (10 Watts )
NCAR/NCEP ECMWF
1.2 1 0.8 0.6 0.4 0.2 0 -90
The Atlantic Ocean
15
-60
-30
0 Latitude
30
60
90
Trenberth et al. 2001
The importance of the THC in the present climate Surface air temperature
NCAR/NCEP reanalysis
Stommel THC Model
The THC is a key factor to explain past abrupt climate changes
Alley (2000)
IPCC TAR WG1 Report
Dickson et al., Nature, April 2002
Based on Bryden et al., Nature, 2005 25
Transport across the North Atlantic at 25°N (Sv)
20 15 10 5 0 -5 -10 -15 1950 1960 1970 1980 1990 2000 2010
Southward Transport 1000–3000 m 3000–5000 m Northward Transport Below 5000 m
• Error Bar
Above 1000 m
Integrated Assessment Model
Base case GHG emissions
Dynamic Integrated Climate Economy (DICE) Model
IPCC-Bern Model
Freshwater Addition To North Atlantic (²T c, )
Stommel-Saltzman Model
Change in THC Intensity (K)
+
GHG Concentration
Temperature Change (²T 2x)
Change in GHG emissions
Tax on Carbon
0.7 0.6
Subjective Probability Distributions
3 2.5
Uniform Weibull Beta
Probability density function
0.5 0.4 0.3 0.2 0.1 0 0 1 2 3 4 5 6 Climate sensitivity, ²T 7
2x
Probability density function
8 (°C) 9 10
2 1.5 1 0.5 0
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 –1 Hydraulic sensitivity, (°C)
0.7 0.6
Uniform Weibull Beta
2
Uniform Weibull Beta
Probability density function
Probability density function
0.5 0.4 0.3 0.2 0.1 0 0 0.5 1 1.5 K 2 2.5 3 3.5
1.5
1
0.5
0
0
0.2
0.4
0.6 0.8 ²T (°C)
C
1
1.2
1.4
20
800 700 600 500 400 300 2000
(b)
Carbon dioxide emission (GtC/year)
15
CO 2 concentration (ppmv)
10
2xCO 2
5
(a)
0 2000
2050
2100 Year
2150
2200
2050
2100 Year
2150
2200
5
0.7
Temperature change from 1900 (°C)
4 3 2 1 0 2000
(c)
Likelihood of a THC shutdown
0.6 0.5 0.4 0.3 0.2 0.1 0 2000
(d)
2050
2100 Year
2150
2200
2050
2100 Year
2150
2200
20
Expected value of minimum THC intensity over 2005 to 2205 (Sv)
15
10
5
0
-5 0 0.5 1 1.5 2 2.5 3 3.5 4 Maximum temperature increase from 1900 (°C)
20
800 700 600 500 400 300 2000
(b) Tax in 2005 ($/tC) 0 10 20 50 75 100
Carbon dioxide emission (GtC/year)
15
10
Tax in 2005 ($/tC) 0 10 20 50 75 100 (a)
CO 2 concentration (ppmv)
2xCO 2
5
0 2000
2050
2100 Year
2150
2200
2050
2100 Year
2150
2200
5
0.7
Temperature change from 1900 (°C)
4 3 2 1 0 2000
(c) Tax in 2005 ($/tC) 0 10 20 50 75 100
Likelihood of a THC shutdown
0.6 0.5 0.4 0.3 0.2 0.1 0 2000
(d) Tax in 2005 ($/tC) 0 10 20 50 100
2050
2100 Year
2150
2200
2050
2100 Year
2150
2200
Probability of a THC Collapse
0.8 0.7
Maximum probability of a THC collapse through 2205
0.6 0.5 0.4 0.3 0.2 0.1 0 (B) 0
5 cents per gallon gasoline
50
6 pence 100per litre petrol 150
200
Initial tax ($/ton of carbon)
SAT Difference, Jan
SAT Difference, July
National Snow and Data Center 2004
http ://news.bbc.co.uk/2/hi/science/na tu re/4857832.stm Unexpected warming in Antarctica By Jonathan Fildes BBC News science reporter Winter air t emperatures over Antarctica have risen by more than 2C in the last 3 0 years, a new study shows. Research published in t he US journal Science says the warming is seen across the whole of the continent and much of the Southern Ocean. The study questions the reliability of current climate models that fail to simulate the temperature rise. In addition, the scientists from the British Antarctic Survey (BAS) say the cause of the warming is not clear. It could be linked to increases in greenhouse gases in the a tmosphere or natural variations in Antarctica's climate system. Scientists are keen to understand the change in temperatures over the continent as the region holds enough water in its ice to raise sea levels by 60 metres.
http://www.nytimes.com/2006/03/03/science/03cndmelt.html?pagewanted=print -----------------------------------------------------------------------March 3, 2006
Antarctica Surveys Show Melting Ice Is Causing Rising Sea Levels
By ANDREW C. REVKIN
Two new satellite surveys show that warming air and water are causing Antarctica to lose ice faster than can be replenished by interior snowfall and thus are contributing to r ising global sea levels. The studies differed significantly in estimates of how much water was being added to the oceans this way, but their authors said that the work added credence to recent conclusions that global warming caused by humans was l ikely to le ad to h igher sea levels than previous studies had predicted. The earlier projections presumed that snowfall over Antarctica, as well as Greenland, would increase as warming added moisture to the air, compensating for the losses of i ce from crumbling or melting along coasts. Several independent experts agreed with the new conclusions, saying they meshed both with more localized studies of trends in Antarctica and with evidence from warm spells before the last ice age.
Fri, 10 Mar 2006 http://news.bbc.co. uk/2/hi/science /nature/4 790238.stm
Polar ice sheets sh net loss ow
By Paul Rincon BBC News sc ience reporter
There is a net l oss of ice t o the ocean from the Greenland andAntarctic ice sheets, a study has found. In one of the most c omprehens ive studies of i ts type, satellite data was used to plot changes in the height of the ice sheets between 1992 and 2002. Writing in the Journa of Glaciology, a US team says that 20 l billion tonnes of water are added to oceans each year. Mass changes in the ice sheets match predictions from computer mode of global climate change they say. ls , Dr H Jay Zwa lly, of the US space agency (Nas Goddard a) Flight Center in Maryland, and colleagues analysed radar altimeter data from two European remote -sensing satellites, ERS-1 and ERS-2, as well as Nasa's plane-based Airborne Topogr aphic Mapperinstrument. The survey documents extens ive thinning of the West Antarctic ice shelves, but a thickening in the East of the continent, though not by a s much as some other studies have sh own. It shows the i nterior of Greenland is gaining mass due to increased snowfall, but the edges are getting thinner. Compet ing forces This mass gain is something which computer models of climate have predicted.
http://www.nytimes.com/2006/03/15/science/earth/15ice.html?_r= 1&oref=slogin&pagewanted=print -----------------------------------------------------------------------March 15, 2006
Ice Retreats in Arctic for 2nd Year; Some Fear Most of It Will Vanish
By ANDREW C. REVKIN
For the second year in a row, the cloak of sea ice on the Arctic Ocean failed to grow to its normal winter expanse, scientists said yesterday. The finding led some climate experts to predict a record expansion of open water this summer. "We keep looking for the ice to recover, but it isn't," said Mark C. Serreze, a senior scientist at the National Snow and Ice Data Center in Boulder, Colo., which monitors the region using satellites. "Unless conditions turn unusually cold this spring and summer, we may be looking at sea ice losses in 2006 that will rival what we saw in 2005." The ice retreat recorded last September was the biggest since satellites began routine monitoring in 1979 and was probably the biggest in 100 years, according to Dr. Serreze's research group and an independent University of Illinois team. The new findings on winter ice were first reported yesterday in the British newspaper The Independent. Next week, when the Arctic begins six months of daylight, the warming trend is likely to be amplified by the shift from ice to
Outline
• Climate Change Primer • Causes of the Observed Warming • Projections of Climate Changes and Their Impacts • Abrupt Climate Change – Shutdown of the Atlantic Thermohaline Circulation • Movie: Renew US