The Global Warming Challenge:

Can policy catch up with the science?

 Michael OppenheimerPrinceton University

for Washington DC Regional

Conference7 March 2009

TrappedRadiationWarmsEarth’sSurface

The Greenhouse Effect

IPCC AR4 Ch 1

Going to the ends of Earth for evidence

http://earthobservatory.nasa.gov/Study/Paleoclimatology_IceCores/

The Greenhouse Problem

IPCC WGI AR4

Fossil fuel use, driven by economic andpopulation growth, is the major cause

IPCC AR4 SYRSources

Total GHG emissions (billions of tons/year)

IPCC AR4 SYR

IPCC AR4

10

9

8

7

6

5

4

3

2

1

0

Em

issi

ons

(bill

ions

of

tons

CO

2/y

r)

1970 1980 1990 2000Year

Electricity plants

Industry (excl. cement)

Road transportationResidential/services sectors

Deforestation Other

RefineriesInternational transport

total emissions ≈ 36 billion tons

CO2/yr

Rapid growth in electric power and transport

Climate system primed for a big change

CO2 TodayNature 453, p.292

Physical reality outpacing responses

• Long-lived emissions, long-term commitment

• Changes already underway, more to come

• Demonstrated limits on our ability to adapt to extreme events

• Modest warming (about 20C) may imply unmanageable changes

• Window to act to avoid such warming closing rapidly

known forsome time

recent developments

CO2 accumulation, and

consequences,very persistent:How to avoid discounting?

CO2

(ppm)

∆T(0K)

Sea levelThermal

Exp.

(m)Solomon et al PNAS 2009

IPCC AR4 WGI SPM

Pervasive climate change already underway:

•Temperature

•Sea level

•Ice (glaciers) and snow

•Extreme heat( ), cold( )

•Rainstorm intensity and drought ( )

•Tropical cyclones

•Ocean acidity

Arctic Sea Ice Pack is Shrinking: Partly due to greenhouse gases, partly

natural

NSDIC

September Sea IceExtent, 1979-2008

Glaciers are retreating

1979 Today

Glacier length,globally IPCC AR4 WGI

Drought Intensity

Increasing

IPCC AR4 WGI

Species observed to be moving up and north to avoid warming...

Lenoir et al Science 2008

Comparison:1905-1985

vs. 1986-2005 for western

Europe

...but some species have nowhere to go

Photo: Leonie Haimson

Future: Emissions and global temperature projected to keep on

climbing

IPCC AR4 SYR

Warming 1900 - 1990

Future Warming

Futureemissions

GEO339 Class 9 17

IPCC AR4TS

What makes these projections credible?

What extremes of climate are likely to intensify?

• More heat, less cold

• More drought

• More intense precipitation and flooding

• Changed ecosystems, species losses

• Higher sea level, maybe much higher

...with implications for food, drinking water, infrastructure, disease, ecosystems and species

But cool periods (like this winter) could occur, too

Courtesy Ron Stouffer, GFDL

Over long term, killer heat waves become the norm

Extreme Summer 2003:

About 35,000 people

in Europesuccumb to

extremeheat...

“normal” summer

model of “normal”

model of future

IPCC AR4 WGI

Large changes in water for drinking, food(Year 2050)

Milly et al, Nature, 438, 347-350, 2005.)

Food production tends to decline, low latitudes, 1-30C

Intensified precipitation

already problematic

IPCC AR4 WGI

Ecosystems expected to shift, species disappear

Up to 30% at risk of extinction, 1-30C warming

Role of Ocean Acidification?

Various Estimates of Upper Limit for Sea Level Rise

Dut

ch e

st.

Ger

man

est

.

Rahmstorf 2

007

Data

Until 2100:18 – 59 cm + X (IPCC 2007)

50 – 140 cm (Rahmstorf 2007)55 – 110 cm (“high end”, Delta Commission 2008)

80 – 200 cm (Pfeffer et al. 2008)1.2m Grinsted et al (not shown)

Until 2200:150 – 350 cm (“high end”, Delta Commission

2008)

Until 2300:250 – 510 cm (German Advisory Council on

Global Change, WBGU, 2006)

Courtesy of Stefan Rahmstorf

IPCCrange

Predicted sealevel rise could prove disastrousin some regions

Courtesy J. Broadus

US, too, needs to develop adaptation strategies. Instead, we are doing this…

Courtesy Norm Psuty

Upper bound determined by behavior of ice sheets...

West Antarctic Ice Sheet Greenland Ice Sheet

WestAntarctica

(WAIS)

EastAntarctica

5m60m

7m

...but we lack models that can reliably project

6-meter

sea level

rise

National Snow and IceData Center 2004

Hazard is clearbut timescale and

critical T are not:

Would rates of risereach

~meter/100yrOr

~meter/1000yr??

Buttressing by ice shelves may be a key factor...

But we lack a satisfactory continental ice-sheet model

Groundingline

(Modified from IPCC AR4 WGI)

Nature/Vol. 419/12 September 2002, pg. 189

Last Interglacial (LIG):Poles 3-50C warmer....

(Similar to outcome of 1-40C global increase in future)

Could this really happen? We Can Also Learn from the Past

Locations of sea level indicators for LIG (Kopp et al 2009)

... sea level was 6-9m higher...

...and apparently rose quickly

(Kopp et al 2009)

Assessment changed: Risk more severe (Smith et al 2009)

Climate Wheel of Fortune

Courtesy MIT joint program

What policies and institutions, international

and domestic, are needed?

Key question for policy makers:

1. Facilitate adaptation, already a key issue, even in developed

countries

2. Legislate Domestic Cap on Emissions

Pew Center for GCC 38

3. Provide other incentives and mandates to

implement existing technologies

4. Decide what are “common but differentiated responsibilities”...and implement with a treaty

40

NY Times 2 07 09

5. Provide incentives for R&D and commercialization of emerging

technologies

Socolow, Sci. Am. July 2005

Statoil CCS operation, AlgeriaFrom Socolow, Sci Am 2006

Carbon capture?

Nuclear?

Solar?

What’s there to work with: Current Regulatory Setting

• EPA/DoE/DoT regulatory action

• US state–level initiatives: links abroad?

• Litigation, and threat thereof

• Kyoto Protocol Part II?

• Group of 15: parallel tracks while gathering 67 votes?

• Private-sector actions

Reason for hope?US CO2 emissions declined as economy continued to grow

1990 1995 2000 2001 2002 2003 2004 2005 2006

Emiss

ions

Years

Net CO2 Emission

Fossil Fuel Combustion

Electricity Generation

Transportation

Industrial

Residential

Commercial

Oil price

Emissions

USEPA