The Modeling of Climate and Climate Change; can we trust model predictions?
CE 401 Climate Change Science and Engineering modeling of climate change predictions from models
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Transcript of CE 401 Climate Change Science and Engineering modeling of climate change predictions from models
CE 401
Climate Change Science and Engineering
modeling of climate changepredictions from models
21 February 2021
team selection and project topic proposal (paragraph): due TODAY 2/21
poster project due Thursday - electronically
exam on first half of class: 3.1.2012
some pre-warned questions for the exam on the 1st :
• what is the average global percent increase in [CO2]/yr since 1959?
• what is the solar energy input [w/m2] at the top of the Earth’s atmosphere?
• what is the average albedo of the Earth [%]?
• what is the solar cycle variability in solar output measured at top of Earth’s atmosphere? [%]
• how many degrees [°C] is the Earth warmer with greenhouse gases than without?
• what ~ percent of global carbon emissions stays in the Earth’s atmosphere?
• what is the pre-industrial (1750) level of [CO2] [ppm]?
• what is the current level of [CO2] [ppm]?
• the carbon cycle
• where does CO2 come from and where does it go
• key components of the climate system
• what goes into a climate model
• what are feedback mechanisms
•
where are we in the syllabus: latest version always on website
source: IPCC 2007 The Climate System - very complicated
components of the system
speeds in the system
modeled global temperature changes from various [CO2] changes
feedbacks are important and modify “normal” models significantly
Figure 8.14
climate feedback parameters: WV=water vapor, C=cloud, A=albedo,LR=lapse rate,
summary of model results for feedbacks
IPCC
Salawitch
the models
Figure 9.1
components of modeled global temp change 1890-1990 (a) solar forcing, (b) volcanoes, c)GHG, (d) tropospheric and stratospheric ozone changes, (e) sulphate aerosol forcing,(f) sum of all forcings, for 1000mb to 10 mb, 0 - 30 km.
pressureheightabovesurface
solarvolcanoes
GHG ozone
sulphate aerosol total
relative radiative forcings 1890 – 1990 from models
what does the IPCC have to say about models and the past 100 years
detection and attribution of causes
basis for attribution of causes for climate change:
• detection: process of demonstrating that climate has changed in some definedstatistical sense, without providing a reason for that change
• attribution of causes: process of establishing the most likely causes for the detectedchange with some defined level of confidence.
Figure 8.5a) observed meanannual precip (cm)for 1980-1999
b) multi-model meansame time period
do predictions agreewith observations
precipitation – obsvd & modeled
IPCC
Observations
Natural + Human-induced
With human-induced influenceWith human-induced influence
Observations and Model ComparisonTemperature Change, 1900 - Present
Natural
Without human-induced influenceWithout human-induced influence
black = observations red = modeled natural + human blue = modeled natural alone
influence of anthropogenic and natural radiative forcings in models:
• significant cooling due to aerosols is a robust feature of a wide range of detectionanalyses
• GHG by themselves would have caused more than the observed warming
• high variance between models - how to identify the aerosol fingerprint (short life)
• using nearly any solar model shows that solar forcing cannot match the observed change
• nonlinearities are not understood (e.g. do forcings just add - most assume this)
synthesis of observed & modeled climate changes – IPCC 2007
IPCC statements on Detection
“little observational evidence of a detectable human influence on climate”
1990 Report
“The balance of evidence suggests a discernible human influence on global climate” 1995 Report
“There is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities”, “warming over the 20th century is very unlikely to be due to internal variability alone as estimated by current models”
2001 Report
“the observed widespread warming of the atmosphere and ocean, together with icemass loss, support the conclusion that it is extremely unlikely that global climatechange of the past 50 years can be explained without external [human] forcing, and very likely that it is not due to known natural causes alone.”
2007 Report
basis for attribution of causes for climate change:• detection: process of demonstrating that climate has changed in some defined
statistical sense, without providing a reason for that change• attribution of causes: process of establishing the most likely causes for the detected
change with some defined level of confidence.
this is the “scientific” consensus, is it right?
I have been dismayed over the bogus science and media hype associated with the (dangerous) human-induced global warming hypothesis. My innate sense of how the atmosphere-ocean functions does not allow me to accept thesescenarios. Observations and theory do not support these ideas. (Professor Emeritus William Gray, CSU, 2006)
Predictions of harmful climatic effects due to future increases in hydrocarbon use and minorGHG like CO2 do not conform to current experimental knowledge, Robinson et al, 2007
On the most important issue, the IPCC’s claim that “most of the observed increase in global average temperatures since the mid-twentieth century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations [emphasis in theoriginal],” NIPCC reaches the opposite conclusion — namely, that natural causes are very likely to be the dominant cause. Non-governmental International Panel on ClimateChange (NIPCC - http://www.nipccreport.org/)
contrarians
Climate Projections for the 21st century
(based on the models)
Revelle and Suess (1957): “human beings are now carrying outa large scale geophysical experiment of a kind that could nothave happened in the past nor be reproduced in the future. Within a few centuries we are returning to the atmosphere and oceans the concentrated organic carbon stored in sedimentary rocks over hundreds of millions of years”
Singer , Hot Talk, Cold Science (1997): Industrialized nationsare poised to adopt policies that will cost hundreds of billions of dollars “to mitigate disasters that exist only on computer printouts and in the feverish imaginations of professional environmental zealots”
results of the models – the predictions and the assignment of cause - are a verypolarizing issue
the models use a set of economic scenarios, from “business as usual” = just keep ramping up carbon useage (A2), to models that take into account economic changes to a service/inofrmation based economy with reductions inmaterial intensity and use of clean and resource-efficient technologies (B1)
scenario assumptions:• fossil fuel use• population change• economic growth• technological innovation• attitudes to social and environmental sustainability• land use change
Figure 10.4
multi-model means of surface warming relative to 1980-1999 for various scenarios.Shading shows 1 std dev range. B1, A1B, A2 are low, med, hi scenarios. # givenumber of models run into that period
various scenarios of warming based on various economic models
IPCC 2007
Figure 10.12
multimodel mean changes for A1B scenario – 2090 relative to 1990
extreme events:• increased risk of more intense, more frequent and longer lasting heat waves
• decrease in the diurnal temp range in most regions
• fewer frost days
• longer growing season
• increased summer dryness and winter wetness in NH midlats and high lats
• increase in extreme rainfall intensity
• evidence that future tropical cyclones could be come more severe
as it usually appearsin print - not adjustedfor a baseline $$ - andin Al Gore’s film
same data adjustedfor a baseline $$
IPCC 2007
Projected changes in annual temperatures for the 2050s
The projected change in annual temperatures for the 2050s compared with the present day, when the climate model is driven with an increase in greenhouse gas concentrations equivalent to about 1% increase per year in CO2
BW 11
source: GISS
-30%-10 0 10+30%
South Florida: 1-m rise in Sea Level
Change in January Average Daily Maximum Temperature (doubling of CO2)
source: Hotchkiss and Stone (2000)
Change in July Average Daily Precipitation (doubling of CO2)
source: Hotchkiss and Stone (2000)
Present
CO2 doubling
by 2050
Vegetation Changes for Modeled Doubling of Carbon Dioxide
source: IPCC, 1996
Temperate forests
Grasslands
Deserts
Savanna
Tropical seasonalforest
Tropical moistforest
Ice
Tundra
Boreal forests
Color Code: now
x 2 CO2
Changescurrent --> 2050
Peak 8-Hr Ozone [ppbv]
(EPA Standard = 80 ppbv)
WSU/LAR - Lamb et al.
Current
Difference
Future
ozone air pollution
differencedifference
Precipitation increases very likely in high latitudes
Decreases likely in most subtropical land regions
winter summer
Regional Climate ModelingPacific NW
• temp increases: 2.2F/2025, 3.5F/2045, 5.9F/2080• April 1 snowpack down by 30% across state by 2025, down 40% by 2045
• primary impact on Puget Sound will be a shift in the timing of peak river flowfrom late spring to late winter• shorter irrigation season• annual hydro production will decrease by a few %
• reservoir systems will likely be less able to supply water to all users – 30% by 2025• due to increased summer temps, area burned by fire is expecdted to double by 2045• rising stream temps will likely reduce quality and extent of salmon habitat• warming is expected during all seasons• sea level increases 2-13 inches by 2100• projected changes in annual precipitation averaged over all models are small (1-2%)• impact of climate change on crops will be mild in short term with increasing effects
• yields of dry land wheat will increase 2-8% by 2025
a quick look at global energy sources and projected demand
Change in CO2 Emissions from Coal (2007 to 2009)
Global Carbon Project 2010; Data: Gregg Marland, Thomas Boden-CDIAC 2010
92% of growth
-50
0
50
100
150
200
250
300
China USIndia World
CO2 e
miss
ions
(Tg
C y-1
)
350
global energy production by type
greenhouse gas emissions
global GHG emissions (anthropogenic)
to 2004
Fossil Fuel CO2 Emissions: Top Emitters
Global Carbon Project 2010; Data: Gregg Marland, Tom Boden-CDIAC 2010
1990 95 2001 05 200997 99 03930
400
800
1200
1600
2000Ca
rbon
Em
issio
ns p
er y
ear
(C to
ns x
1,0
00,0
00)
China
USA
Japan
Russian Fed.India
07
2009
Time (y)
Top 20 CO2 Emitters & Per Capita Emissions 2009
Global Carbon Project 2010; Data: Gregg Marland, Thomas Boden-CDIAC 2010; Population World Bank 2010
0
500
1000
1500
2000
2500
CHINAUSA
INDIA
RUSSIAJA
PAN
GERMANYIRAN
SOUTH KOREA
CANADA
UNITED KINGDOM
MEXICO
SAUDI ARABIA
SOUTH AFRICA
INDONESIAITALY
BRAZIL
AUSTRALIA
FRANCE (inl. M
onac
o)
POLAND
SPAIN0
1
2
3
4
5
6
Tota
l Car
bon
Emiss
ions
(to
ns x
1,0
00,0
00)
Per Capita Emissions
(tons C person y-1)
Human Perturbation of the Global Carbon Budget
Global Carbon Project 2010; Updated from Le Quéré et al. 2009, Nature Geoscience; Canadell et al. 2007, PNAS
5
10
10
5
1850 1900 1950 2000
2000-2009(PgC)
atmospheric CO2
ocean
land
fossil fuel emissions
deforestation
(Residual)
Sink
Sour
ce
Time (y)
CO2 f
lux
(PgC
y-1)
2.3±0.4(5 models)
4.1±0.1
7.7±0.5
1.1±0.7
2.4
ppp=purchasing power parity
toe per capita
1971 - 2003 by region; mtoe = million tonnes of oil equivalent
Who has the oil?USA
China
India
(http://www.energybulletin.net/37329.html)
Total global energy demand
70%increase
(International Energy Outlook 2006)
Energy use by type
(International Energy Outlook 2006)
Fossil Fuel Emissions: Actual vs. IPCC Scenarios
Updated from Raupach et al. 2007, PNAS; Data: Gregg Marland, Thomas Boden-CDIAC 2010; International Monetary Fund 2010
Foss
il Fue
l Em
issio
n (Pg
Cy-1)
5
6
7
8
9
10
1990 1995 2000 2005 2010 2015
Full range of IPCC individual scenarios used for climate projections
A1B Models AverageA1FI Models AverageA1T Models AverageA2 Models Average
B1 Models AverageB2 Models Average
ObservedProjected
Time (y)