The Latest Scientific The Latest Scientific Assessment of Climate Assessment of Climate Change and its Impacts Change and its Impacts on World Food Securityon World Food Security

—the IPCC Reports—the IPCC Reports

William E. EasterlingWilliam E. Easterling

Penn State UniversityPenn State University

The FactsThe Facts

Fact 1: The Fact 1: The Greenhouse Effect is Greenhouse Effect is

realreal

Without the Greenhouse Effect, the Earth’s surface temperature averages ~30˚C colder

NATURAL GREENHOUSE EFFECT

Fact 2—the chemistry of the global atmosphere is changing

ENHANCED GREENHOUSE EFFECT

What is the oscillation

due to?

Historical CO2 measurements

Began in 1958

Prehistoric Greenhouse Gas Measurements

Recent rise of atmospheric greenhouse gas Recent rise of atmospheric greenhouse gas concentrations is unprecedented in last 10,000 yrs—ice concentrations is unprecedented in last 10,000 yrs—ice

cores suggest even the last 650,000 yrscores suggest even the last 650,000 yrs

IPCC-SPM, 2007

Fact 3—human activity is Fact 3—human activity is the source of the rise in the source of the rise in greenhouse gas greenhouse gas concentrationsconcentrations

Fact 4—Fact 4—Ipso factoIpso facto from the from the previous two facts: radiative previous two facts: radiative forcing of the atmosphere is forcing of the atmosphere is

increasingincreasing

Growth in fossil fuel emissions highly Growth in fossil fuel emissions highly correlated with growth in atmospheric correlated with growth in atmospheric

COCO22

Total radiative forcing—a measure of the stengthening of the greenhouse effect—has increased by 20% (~+1.5Wm-

2) over the past decade.

Several lines of Several lines of evidence have evidence have

converged giving high converged giving high confidence that the confidence that the Earth’s climate is Earth’s climate is changing………changing………

UK going Mediterranean in 2003Katrina fueled bywarm Gulf water

Research has narrowed Research has narrowed the attribution of the attribution of

observed warming to observed warming to human activity…….human activity…….

General Circulation Models (GCMs) take into account the full three-dimensional

structure of the atmosphere and ocean

Black line is observed temperature

Orange is simulated temperature

Blue is simulated temperature

Rate and amount of warming is dependent on the Rate and amount of warming is dependent on the political, social and economic factors that govern political, social and economic factors that govern

emissionsemissions

Range of warming is ~1-4˚C by 2100

Sustainability World

Early Demographic Transition World

Late Demographic Transition World

Warming to 2030 (~0.8˚C)

warming to 2100 (~2-2.2˚C)

White areas are where less than 2/3 of White areas are where less than 2/3 of models agree; stippled areas are where models agree; stippled areas are where more than 9/10 of models agreemore than 9/10 of models agree

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Effects on Global Effects on Global Food SecurityFood Security

Green = with adaptation

Red = without adaptation

= reference line for current yields

Cereal Yield Response to Warming—Temperate vs. Tropical Regions

(with and without simulated adaptation)

Temperate yields tend to thrive until +3˚C Tropical yields tend to

decline immediately

Simple adaptations extend temperate crops to +4-5 ˚C but tropical yields only to +2-3˚C

One of the earliest One of the earliest effects of climate effects of climate change is likely to be change is likely to be the range of crop pests the range of crop pests and diseasesand diseases

Simulated spread of Simulated spread of soybean rust into the U.S. soybean rust into the U.S. with Hurricane Ivan was with Hurricane Ivan was scary accurate!scary accurate!

Pan and Yang, 2004 Science

What happens when What happens when conventional adaptive conventional adaptive measures are measures are exhausted?—will exhausted?—will biotechnology be the biotechnology be the answer?answer?

Global Area of Transgenic Crops: Global Area of Transgenic Crops: Industrial and Developing Industrial and Developing Countries (1996- 2000)Countries (1996- 2000)

0

5

10

15

20

25

30

35

40

1995 1996 1997 1998 1999 2000

Mil

lion

hec

tare

s

IndustrialcountriesDevelopingcountries

Biofuels as Adaptation Biofuels as Adaptation and Mitigation: Does and Mitigation: Does energy have to energy have to compete with food?compete with food?

Availability of Currently Availability of Currently Unused Arable Land for Unused Arable Land for Food and/or Bioenergy Food and/or Bioenergy Crops (est. by FAO)Crops (est. by FAO)

SummarySummary Greenhouse effect is getting strongerGreenhouse effect is getting stronger

Multiple lines of evidence of warming are consistent Multiple lines of evidence of warming are consistent and more certain than everand more certain than ever

Models are making the case that most of the Models are making the case that most of the warming is attributable to GHG emissionswarming is attributable to GHG emissions

Warming by end of century could be equal to 60-Warming by end of century could be equal to 60-80% of the warming since the last ice age until now80% of the warming since the last ice age until now

Global food production likely to be adequate overall Global food production likely to be adequate overall but unequal distribution harming food security in but unequal distribution harming food security in the tropicsthe tropics