FROM AIR POLLUTION TO GLOBAL CHANGE AND BACK:FROM AIR POLLUTION TO GLOBAL CHANGE AND BACK:

Towards an integrated international policy for air pollution and climate changeTowards an integrated international policy for air pollution and climate change

Daniel J. JacobHarvard University

NUMBER OF PEOPLE LIVING IN U.S. COUNTIES NUMBER OF PEOPLE LIVING IN U.S. COUNTIES VIOLATING NATIONAL AIR QUALITY STANDARDS, 1999VIOLATING NATIONAL AIR QUALITY STANDARDS, 1999

EPA [2001]

124 ppbv84 ppbv

Carbon monoxide (CO)

Lead

Nitrogen dioxide

Ozone (O3)

Particles < 10 m(PM10)

Particles < 2.5 m(PM2.5)

Sulfur dioxide(SO2)

Any pollutant

ANNUAL MEAN PARTICULATE MATTER (PM) ANNUAL MEAN PARTICULATE MATTER (PM) CONCENTRATIONS AT U.S. SITES, 1995-2000CONCENTRATIONS AT U.S. SITES, 1995-2000

NARSTO PM Assessment (draft), 2002NARSTO PM Assessment (draft), 2002

PM10 (particles > 10 m) PM2.5 (particles > 2.5 m)

Red circles indicate violations of national air quality standard:50 g m-3 for PM10 15 g m-3 for PM2.5

ASIAN DUST CLOUD OVER THE WESTERN U.S. ASIAN DUST CLOUD OVER THE WESTERN U.S. (APRIL-MAY 1998)(APRIL-MAY 1998)

GOES Satellite Image PM10 West Coast

R. Husar, Washington U.

EPA REGIONAL HAZE RULE: FEDERAL CLASS I AREAS EPA REGIONAL HAZE RULE: FEDERAL CLASS I AREAS TO RETURN TO “NATURAL” VISIBILITY LEVELS BY 2064TO RETURN TO “NATURAL” VISIBILITY LEVELS BY 2064

Acadia National Park

clean day moderately polluted day

http://www.hazecam.net/

Places new emphasis for understanding long-range transport

GOOD vs. BAD OZONE (OGOOD vs. BAD OZONE (O33))

NOx = NO + NO2: nitrogen oxide radicalsVOC (volatile organic carbon) = light hydrocarbons and substituted organic compounds

MEAN NUMBER OF SUMMER DAYS (1980-1998) MEAN NUMBER OF SUMMER DAYS (1980-1998) EXCEEDING THE U.S. OZONE AIR QUALITY STANDARD EXCEEDING THE U.S. OZONE AIR QUALITY STANDARD

(84 ppbv, 8-hour average)(84 ppbv, 8-hour average)

EPA/AIRS data [Lin et al., 2001]

THE TROPOSPHERIC OZONE BACKGROUNDTHE TROPOSPHERIC OZONE BACKGROUNDAT NORTHERN MIDLATITUDES AT NORTHERN MIDLATITUDES

HAS INCREASED SHARPLY OVER PAST 100 YEARSHAS INCREASED SHARPLY OVER PAST 100 YEARS

Ozone trend from European mountain observations [Marenco et al., 1994]

THIS OZONE BACKGROUND IS A SIZABLE INCREMENT THIS OZONE BACKGROUND IS A SIZABLE INCREMENT TOWARDS VIOLATION OF U.S. AIR QUALITY STANDARDSTOWARDS VIOLATION OF U.S. AIR QUALITY STANDARDS

(even more so in Europe!)(even more so in Europe!)

0 20 40 60 80 100 120 ppbv

Europe(seasonal)

U.S.(8-h avg.)

U.S.(1-h avg.)

preindustrial presentbackground

Europe (8-h avg.)

SURFACE OZONE ENHANCEMENTS CAUSED BYSURFACE OZONE ENHANCEMENTS CAUSED BY

ANTHROPOGENIC EMISSIONS FROM DIFFERENT CONTINENTSANTHROPOGENIC EMISSIONS FROM DIFFERENT CONTINENTS GEOS-CHEMmodel, July 1997

North America

Europe

Asia

Li et al. [2002]

Growth of Asian emissions over the next decades will Growth of Asian emissions over the next decades will increase role of background for ozone air quality in U.S.increase role of background for ozone air quality in U.S.

109 atoms N cm-2 s-1

AnthropogenicNOx emissions[IPCC, 2001]

2000

2020

“Optimistic” IPCC scenario: OECD, U.S. 20%, Asia 50%

TREND IN NORTHERN HEMISPHERIC TREND IN NORTHERN HEMISPHERIC SURFACE TEMPERATURE OVER PAST 1000 YEARSSURFACE TEMPERATURE OVER PAST 1000 YEARS

IPCC [2001]

EFFECTS OF GREENHOUSE GASES AND AEROSOLS EFFECTS OF GREENHOUSE GASES AND AEROSOLS ON CLIMATEON CLIMATE

Greenhouse gas layer(transparent to solar,

absorbs in IR)

Greenhouseeffect (warming)

Terrestrial emission (IR)

Aerosol layer(scatters solar,

transparent in IR)

Solar radiationreflected to space(cooling)

EARTH SURFACE

HISTORICAL TRENDS OF GREENHOUSE GASES HISTORICAL TRENDS OF GREENHOUSE GASES AND AEROSOLSAND AEROSOLS

Greenhouse gases

Aerosols

IPCC [2001]

Carbon dioxide

Methane

Nitrous oxide Sulfur

LINK BETWEEN AIR POLLUTION AND CLIMATE FORCINGLINK BETWEEN AIR POLLUTION AND CLIMATE FORCING

GLOBAL RADIATIVE FORCING OF CLIMATE, 1750-present [IPCC, 2001]GLOBAL RADIATIVE FORCING OF CLIMATE, 1750-present [IPCC, 2001]

POLLUTANT-RELATED

OH

BLACK CARBON: A MAJOR “GREENHOUSE” AEROSOLBLACK CARBON: A MAJOR “GREENHOUSE” AEROSOLIts forcing is likely underestimated in IPCC 2001 reportIts forcing is likely underestimated in IPCC 2001 report

Chin et al. [2000]

DIESEL

DOMESTICCOAL BURNING

BIOMASSBURNING

WHAT DOES THE FUTURE HOLD?WHAT DOES THE FUTURE HOLD?Future emission scenarios from IPCC [2001] Future emission scenarios from IPCC [2001]

A1, A2, B1, B2: four different socioeconomic story lines

NOx: ozone precursor

SO2: aerosol precursor Methane

EFFECTS OF FUTURE CHANGES EFFECTS OF FUTURE CHANGES IN GLOBAL ANTHROPOGENIC EMISSIONSIN GLOBAL ANTHROPOGENIC EMISSIONS

High-ozone days over U.S. Radiative forcing

Standard 50% 50% 50% A1 B1 NMVOC CH4 NOx 2020 2020

Standard 50% 50% 50% A1 B1 NMVOC CH4 NOx 2020 2020

IPCC scenario

Fossil fuel NOx emissions

(2020 vs. present)

Global U.S.

Methane concentration

(2020 vs. present)

A1 +80% -30% +35%

B1 +10% -60% +20%Fiore et al.[2002]