What Does a Warmer Planet Mean for Mortality in the U.S. and India? Implications for Climate Change Policy

Transcription

1 What Does a Warmer Planet Mean for Mortality in the U.S. and India? Implications for Climate Change Policy Michael Greenstone 3M Professor of Environmental Economics Massachusetts Institute of Technology May

2 Questions 1. What is the impact of annual variation in weather on mortality rates in the U.S. and India? 2. Why are the mortality consequences (dramatically) worse in India? 3. What are the projected impacts of climate change on mortality (assuming no adaptation)? 2

3 I. Temperatures Have Been Increasing and Are Expected to Rise Further 3

4 Temperature Increase Under a business-as-usual emissions scenario, the mean annual global temperature is projected to increase by roughly 18% from under 42 F (5.6 C) to about 49 F (9.4 C) between 2000 and

5 Current Daily Temperature Distribution and Projected Change at the End of the Century < > Distribution of Annual Daily Mean Temperatures (F) Average Predicted Change, Hadley 3-A1FI, Error-Corrected 5

6 II. Temperature, Mortality, and Adaptation in the U.S. and India 6

7 Relationship Between Mortality and Temperature in the U.S < >90 Estimated Impact of a Day in 9 Daily Mean Temperature (F) Bins on Annual Mortality Rate, Relative to a Day in the F Bin -2 Std Error Annual Deaths Per 100, Std Error 7

8 Relationship Between U.S. Residential Energy Consumption and Temperature < >100 Estimated Impact of a Day in 10 Daily Mean Temperature (F) Bins on Annual Residential Energy Consumption, Relative to a Day in the F Bin -2 Std Error Annual QBTU +2 Std Error 8

9 Setting: India GDP per capita: $640 Life expectancy: about 65, median age 25 Crude death rate: 8 per 1,000 Agriculture accounts for 22% of GDP and 60% of employment Rural / urban sectors: 75% of population lives in rural sectors (<5,000) Higher poverty rates, 39.4% in Rural vs. 22.5% in Urban (1983) Higher dependence on agriculture (income and food) Rural population s real income more exposed to weather shocks than urban population 9

10 Relationship Between Log Annual Mortality Rate (All Ages) and Daily Temperature in India and U.S. 10

11 Relationship Between Log Annual Mortality Rate (All Ages) and Daily Temperature in India and U.S. 11

12 Temperature and Mortality: Rural Areas Rural Mortality: All-Age Mortality < > Estimated Impact of a Day in 15 Temperature (C) Bins on Log Rural Annual Mortality Rate, Relative to a Day in the C Bin -2 std err coefficient +2 std err 12

13 Temperature and Productivity: Rural Areas Rural Productivity: Aggregate agricultural output per hectare < > Estimated Impact of a Day in 15 Temperature (C) Bins on Log Agricultural Total Product (Sum Weighted by Average Crop Price), Relative to a Day in the C Bin -2 std err coefficient +2 std err 13

14 14 III. Projected Climate Change Impacts

15 Implications of Climate Change Looking into the future: As climate changes throughout the 21st Century, what are the implications for mortality? Under most scenarios, the estimates (based on short-run shocks) will place an upper-bound on the effects of a long-run change 15

16 16 Estimated Impacts of Climate Change in U.S. and India (Assuming No Adaptation) By Temperature Range Percentage Change Low Medium High Temperature Totals Temperature + Precipitation U.S (0.3) (0.8) (1.9) (1.5) (1.5) India (3.0) (4.5) (12.6) (12.5) (14.2) NOTE: In the U.S., the Low/Medium & Medium/High cutoffs are 20 F & 80 F, respectively. In India, they are 16 C (60.8 F) & 32 C (89.6 F).

17 Summary of Findings and Interpretation 1. In US, Small Increase in Mortality Rates and Sharp Increase in Energy Consumption (Air Conditioning) in Response to Hot Days 2. In India, Large Increase in Mortality Rates and Sharp Decline in Agricultural Productivity Unequal Burdens of Climate Change 3. Additional Costs of Climate Change Likely to Emerge as Research Evolves. One Potentially Important Area is on Cognitive Development or Lifetime Health through in Utero or Early Life Exposure to High Temperatures (e.g., Deschenes, Greenstone, and Guryan 2009) 17

18 Policy Implications 1. Slowing Climate Change Requires Global Participation 18

19 Policy Implications 1. Slowing Climate Change Requires Global Participation 2. Climate Change will be Costly to Confront. Low Carbon Energy Sources are Significantly More Expensive than Fossil Fuels. 19

20 Policy Implications 1. Slowing Climate Change Requires Global Participation 2. Climate Change will be Costly to Confront. Low Carbon Energy Sources are Significantly More Expensive than Fossil Fuels. 3. In the U.S., High Levels of Wealth Likely to Protect People from Many Impacts of Climate Change, Including High Temperatures. However, the U.S. is Still Vulnerable to Catastrophes (e.g., Sea Level Rise, Extreme Temperature Increases, etc.) 20

21 Policy Implications 1. Slowing Climate Change Requires Global Participation 2. Climate Change will be Costly to Confront. Low Carbon Energy Sources are Significantly More Expensive than Fossil Fuels. 3. In the U.S., High Levels of Wealth Likely to Protect People from Many Impacts of Climate Change, Including High Temperatures. However, the U.S. is Still Vulnerable to Catastrophes (e.g., Sea Level Rise, Extreme Temperature Increases, etc.) 4. Developing Countries are Unlikely to Devote Substantial Resources to Preventing Climate Change Precisely Due to Low Current Income Levels and Current Vulnerabilities to Current Environmental Factors. 21

22 Policy Implications 1. Slowing Climate Change Requires Global Participation 2. Climate Change will be Costly to Confront. Low Carbon Energy Sources are Significantly More Expensive than Fossil Fuels. 3. In the U.S., High Levels of Wealth Likely to Protect People from Many Impacts of Climate Change, Including High Temperatures. However, the U.S. is Still Vulnerable to Catastrophes (e.g., Sea Level Rise, Extreme Temperature Increases, etc.) 4. Developing Countries are Unlikely to Devote Substantial Resources to Preventing Climate Change Precisely Due to Low Current Income Levels and Current Vulnerabilities to Current Environmental Factors. 22 Challenging Context to Find a Solution to Climate Change

23 Source Papers Deschenes and Greenstone Climate Change, Mortality, and Adaptation: Evidence from Annual Fluctuations in Weather in the US. American Economic Journal: Applied Micro Burgess, Deschenes, Donaldson, and Greenstone Weather and Death in India: Mechanisms and Implications for Climate Change. 23