After reading the WSJ Opinion Piece and regarding predictions about climate change, I am.. 1.Much more skeptical 2.Somewhat skeptical 3.Always been skeptical 4.Still convinced 5.Still strongly convinced

World Food Facts Average ~2700 cal/person Total Calories –from plants: 84% (54% from cereals; rice and wheat are ~1/2) –from animals: 16% –from fish: 1% 40% of the world’s food comes from 20% of cropland that is irrigated Rates of Change –Cereal yield increase in Green Revolution (~ ): 2%/year –Cereal Demand increasing 2%/year –World Cereal Production Peaked in 1975 –Soil loss 15Mha/yr (~1% of arable land per year) –1/4 of arable land degraded in past 50 years The Global Seed Bank, Svalbard Norway

Climate Change in Developing (Agrarian) Countries 1. Where do the Food Insecure live? 2. Projections of climate at the end of the 21 st Century 3. Climate Change and food security in developing nations

Where do the Food Insecure live? What do the food insecure eat? Rice (26%) Wheat (17%) Sugar Cane (8%) Maize (6%) Nuts (5%) Casava (4%) Other (34%) 1 B people are malnourished today 95% are in the tropics/subtropics The food insecure are also the poor. They depend heavily on agriculture for both food an income. Lobell et al. (2008)

Climate Change in Developing (Agrarian) Countries 1. Where are do the Food insecure live? 2. Projections of climate at the end of the 21 st Century (from IPCC) – Focus on those changes that are “very likely” (i.e., those that are either deemed to have a greater than 90% chance to occur “based on quantitative analysis or an elicitation of the expert views”) 3. Climate Change and food security in developing nations

How much Carbon Dioxide will be released into the atmosphere? A1B A2 B1 Atmospheric CO2 Concentration Depends on population and economic projections, future choices for energy, governance/policy options in development (e.g., regional vs. global governance) The most conservative estimate doubles CO 2 from pre-industrial by the end of the Century. More realistic scenarios nearly triple CO 2 –More than anytime since at least 3M years ago –Rate of change is times faster than nature –Time it takes nature to restore to normal levels: 1000s of years

Projected Annual Average Surface Temperature Change: “ ” minus “ ” Average of 21 climate models forced by Scenario A1B. Multiply by ~1.2 for A2 and ~0.7 for B1

Projected Annual Average Precipitation: “ ” minus “ ” Scenario A1B Stippling is where the multimodel average change exceeds the standard deviation of the models There is a robust drying of the subtropics, 20-35N&S. WetterDrier

Climate Change in Developing (Agrarian) Countries 1. Where are do the Food insecure live? 2. Projections of climate at the end of the 21 st Century 3. Climate Change and food security in developing nations Precipitation Temperature Other

Projected Changes in the Central Asia: “ ” minus “ ” Scenario A1B Drying in Central Asia and Southern Europe (~ % reduction of annual mean precip) Dec-FebJune-Aug

The recent drought in the Central Asia ~ 30% annual mean precip deficit Precip Anomaly (mm/month)

The recent drought in the Central Asia Iran: 80% of livestock lost % reduction in wheat & barley Afghanistan: 40% of livestock lost Pakistan: 50% of livestock lost Tajikistan:50% of grain crop lost By the end of the century, similar water stress on agriculture will be the norm throughout the tropics and subtropics due to the climate changes associated with increasing CO 2.

Climate Change in Developing (Agrarian) Countries 1. Where are do the Food insecure live? 2. Projections of climate at the end of the 21 st Century 3. Climate Change and food security in developing nations Precipitation Temperature Other

Let’s examine the 2003 heat wave in Europe How does the summer of 2003 compare with summers in ?

Projections of future temperature Mean Mean Probability Temperature

Projected JJA Average Surface Temperature Change: “ ” minus “ ” Average of 21 climate models forced by Scenario A1B. Multiply by ~1.2 for A2 and ~0.66 for B1

Extreme Heat in Western Europe in 2003: JJA temperature 3.6°C above normal France & N. Italy: 30, ,000 dead of heat stress Italy: 36% drop in maize yields France: 30% decrease in maize and fodder production 25% decline in fruit harvests 21% reduction in wheat yields By 2100, years of similar temperature stress on agriculture will be the norm throughout the tropics and subtropics due to the summer average temperature changes. Refs: UNEP 2007; Easterling 2007; Earth Policy Institute 2006; Eurosurveillence 2005

Growing Season Temperature 2003 France Observed JJA Temp ( )

Projections of Growing Season Temperature Projections use 22 climate models (IPCC AR4) forced by A1B Emission scenario. Variability taken from observations Observed JJA Temp ( ) 2003 France

Projections of Growing Season Temperature The Sahel 2003 France

Projections of Growing Season Temperature By the end of the 21st Century it will be much hotter everywhere In most of the tropics/subtropics, the seasonal average temperature will very likely exceed the warmest year on record Battisti and Naylor 2009

Impacts of Climate Change on Food Security Increasing temperature over the next 50 years will cause decreases in yield: Decrease in grain filling Decrease in spikelet fertility Increased water stress Increased respiration Important for all crops, but especially for wheat, rice and soybeans (nb, these are the C3 crops that would otherwise benefit from increased CO 2 ) and maize Lobell 2007 Wheat Yield in Yaqui Valley, MX Jan-Mar Night Temp (°C)

Reduced yields of wheat, rice and soybeans in the tropics/subtropics –Approximately -10% per 1ºC warming –Est. reduction of 30-40% by 2100 in India, Southern Africa, Middle East, etc. Reduced nutritional content (especially protein in wheat and rice) Increased disease transmission rates Loss of water stored in snow pack and glaciers (e.g., Sierra, Himalaya) –Reduced duration of river supplied water, especially important for India and Bangladesh Impacts of Climate Change on Food Security Impacts of increased temperature (only):

Impacts of Climate Change on Food Security By 2050, many countries in the subtropics will experience: – Typically a % reduction in rainfall (northern and southern Africa, Caribbean, Middle East, etc.) – Increased frequency, duration and intensity of drought – Reduced yields and in some places abandonment of staple crops (many of these regions are marginal for crops presently grown) – Duration and intensity of monsoon (e.g., rice in Indonesia) – Increase in flooding in midlatitudes and tropics (increase intensity of precipitation on drier soils) – Leaching of nutrients in soil Impacts of changing precipitation:

Impacts of Climate Change on Food Security Increased carbon dioxide and plants – Enhanced growth rate for some C3 plants (benefits limited to < 2030AD, and to the extratropics) – Including temperature increases due to CO 2, a net negative impact in tropics/subtropics for all crops (C3 and C4) Effects on soil BGC Effects on plant pathology (reduced protein content and resilience to disease) Sea level rise: about 35cm by 2100 – salinization and loss of arable land Changes in pest and pathogens Other impacts of climate change on agriculture

Summary By 2100, growing season temperatures will very likely exceed the warmest on record throughout the tropics and subtropics – 20-40% reduction in yields of major crops (plant physiology) In subtropics, crops will be further stressed by reduced rainfall Increased CO 2 (fertilization) effect is small (<10% for doubling CO 2 ) Pest and Pathogens (losses ~ double)

Where do the Food Insecure live? The food insecure - depend heavily on agriculture for food and income - live in regions where agriculture will be most stressed by global warming - live in countries that have the greatest population growth rates 1 B people are malnourished today 95% are in the tropics/subtropics Estimates: M more people at risk of hunger by 2080 due to climate change Lobell et al (2008)

The ‘effectiveness (±)’ of the WJ Opinion Piece was a result of ‘sound’ use of: 1.Empirical claims 2.Normative claims 3.Mixed 4.Mostly normative 5.Mostly empirical

How much Carbon Dioxide will be released into the atmosphere? A1B A2 (business as usual) B1 (utopia) Estimates depends on population and economic projections, future choices for energy, governance/policy options in development (e.g., regional vs. global governance) A1B A2 B1 Emissions Covered in Lecture 5 (Yoram)

2010 AD Today Thousands of years before present 2100AD ppm 1850AD 8000BC Carbon Dioxide in the Atmosphere A1B A2 B1 Covered in Lecture 5 (Yoram)

Global Annual Average Surface Temperature Referenced to the Average Temperature Solid lines: average of all models used. Number of models used varies; shaded area is the standard deviation of the models Model Uncertainty Covered in Lecture 5 (Yoram)

Climate changes due to human activity Virtually certain > 99% Very likely >90% IPCC 2007 Yoram, in lecture 5, compare the language used in the various IPCC report. This is a detailed description of some specifics associated with increases in average global land and sea temperatures.

Projected Changes in Africa: “ ” minus “ ” Drying in Northern & Southern Africa projected by more than 16 of 21 models: 10-15% of annual mean in S. Africa; 20-30% in N. Africa (regions that are marginal for agriculture today). About 20% wetter in E. Africa The models diverge for the Sahel: half the models show drying Dec-Feb Scenario A1B June-Aug

Impact on Natural Tropical Ecosystems Though projected climate changes are smaller in the tropics than in the mid and high latitudes, ecothermal species in the tropics will be more negatively affected than those in the midlatitudes (terrestrial and marine) Tewksbury et al 2008 Insects

Impact on Natural Tropical Ecosystems Fitness Tewksbury et al 2008 Species living in the midlatitudes experience large natural temperature swings (e.g., 20 to 30ºC changes from winter to summer) Species in the tropics have experienced very small temperature variability for the past 10,000 years (2 to 4ºC) Time and evolution has made tropics species less resilient to temperature changes

Epilog In June 2009, a meeting of the chief maize breeders. Scientists from Pioneer Seed, Monsanto, two of the International Research Centers, four major universities, etc. All agree: higher temperatures in the subtropics have large negative impacts on maize yield. All have different explanations.

World Food Facts Average ~2700 cal/person Total Calories –from plants: 84% (54% from cereals; rice and wheat are ~1/2) –from animals: 16% –from fish: 1% 40% of the world’s food comes from 17% of cropland that is irrigated Rates of Change –Cereal yield increase in Green Revolution (~ ): 2%/year –Cereal Demand increasing 2%/year –World Cereal Production Peaked in 1975 –Soil loss 15Mha/yr (~1% of arable land per year) –1/4 of arable land degraded in past 50 years The Global Seed Bank, Svalbard Norway

Thank You

Projected Soil Moisture Change: “ ” minus “ ” Scenario A1BWetterDrier

Projected Hydrologic Changes: “ ” minus “ ” Scenario A1B

Projected Annual Average Surface Temperature Change: “ ” minus “ ” Average of 21 climate models forced by Scenario A1B. Multiply by ~1.2 for A2 and ~0.7 for B1