Deforestation & Land Use

1. Deforestation & Land Use Bethany Willett Atmospheric Science Major

2. Papers • “Global Consequences of Land Use” by Jonathan A. Foley, et al. • “The Importance of Land-Cover Change in Simulating Future Climates” by Johannes J. Feddema, et al.

3. Basics of Deforestation • More • Disrupted water cycle • Soil erosion • Species loss

4. Paper 1 “Global Consequences of Land Use” By Foley et al. Topics: Food production Freshwater Resources Forest Resources Regional Climate and Air Quality Infectious Disease Finding a Balance

5. Shrinking Natural Ecosystems • Are land-use activities degrading the global environment in ways that may ultimately undermine ecosystem services, human welfare, and the long-term sustainability of human societies?

6. Consequence 1: Food Production • Croplands & pastures occupy ~40% of land surface • Environmental damage • Increased fertilizer use worse water quality • Soil erosion and reduced fertility • Loss of native habitats less pollinators (bees) • Problem: Trading short-termincreases in food production for long-term losses in ecosystem services

7. Potential Vegetationvs.Agricultural Land cover

8. Consequence 2: Freshwater Resources • Disrupted surface water balance • Runoff and groundwater flow • Increased crop irrigation • Agriculture accounts for ~85% of global consumptive use of water • Reduced flow in rivers • Declining water tables • Degraded water quality • Increases sediments and erosion • Leaches nutrients and chemicals into groundwater, streams, and rivers

9. Forest Resources Consequence 3: • Net loss of ~7-10 million of forest in past 300 years • Land-use practices degrade forest ecosystems • Productivity, biomass, stand structure, and species composition • Introduces pests and pathogens • Changes local meteorological conditions • Afforestation and forest management in areas are acting to improve forest conditions

10. Regional Climate & Air Quality Consequence 4: • Changes in precipitation division • Clearing in the tropics warmer, drier climate • Changes in surface radiation balance • Clearing in temperate and boreal forests cooler climate through increased albedo • Urban “heat islands” • From reduced vegetation cover, impervious surface area, and morphology of buildings • Reduced air quality • Dust sources, biomass burning, vehicle emission patterns • Higher urban temperatures increased

11. Infectious Disease Consequence 5: • Modified transmission of disease • Through habitat modification, road or dam construction, increased proximity of people and livestock • Tropical deforestation upsurge of malaria in Africa, Asia, and Latin America • Even after accounting for changing population density • Disturbs wildlife habitats • ~75% of human diseases have links to wildlife or domestic animals • Increased deaths in extreme climatic events • Hurricane Mitch (1998) – water and vector-borne diseases

12. Finding a Balance

13. Paper 2 “The Importance of Land-Cover Change in Simulating Future Climates” Topics: Purpose Modeling Methods Graphs Results By Feddema et al.

14. Purpose • Evaluate whether future land decisions could alter the outcome of two future IPCC SRES climate simulations • Intergovernmental Panel on Climate Change Special Report on Emissions Scenarios • Include both biogeochemical and biogeophysical processes • Biogeochemical- alter rate of biogeochemical cycles, changing the chemical composition of atmosphere • Biogeophysical- affect absorption and disposition of energy at Earth’s surface • Albedo, sensible and latent heat fluxes, momentum and heat transport

15. Modeling Methods • Used fully coupled Department of Energy Parallel Climate Model (DOE-PCM) • Combined land-cover change and atmospheric forcingsfor two SRES scenarios • A2 scenario- high-impact, 2C warming • B1 scenario- low-impact, 1 C warming (introduction of clean tech) • Used the Integrated Model to Assess the Global Environment (IMAGE) for land-cover projections • Used DOE-PCM natural vegetation data • Created land-cover data sets representing SRES A2 and B1 scenarios

16. Land-cover change Removal of agriculture Change to agriculture

17. Temperature differences • Most significant effects are in mid-latitude and tropical areas • > 2C warming in Amazon • Not same in Indonesia (due to Asian Monsoon) • Opposing signals in Russia • Linked to changes in regional precipitation and teleconnections • Cooling in western U.S • Weakened Hadley circulation increases water availability even with a change to agriculture

18. Changes in Average Diurnal Temperature Range • Land-cover change has more significant impact on DTRs compared to surface temps • Lower DTR is a result of increased daily minimum temps, especially in the Amazon • Lower DTR is a result of decreased daily maximum temps, especially in western U.S.

19. Results • Future land use could have a big impact on regional and seasonal climates • Direct impacts of land-cover change on local moisture and energy balances in tropics and mid-latitude • Impacts related to indirect climate effects through teleconnectionprocesses • Tropical rainforest conversion weakened Hadley circulation and changes in Asian Monsoon circulation • The inclusion of land-cover forcing will improve the quality of regional climate assessments for the IPCC SRES scenarios (and other future climate studies)

20. Overall Conclusions • Modern land-use practices, while increasing the short-term supplies of material goods, may undermine many ecosystem services in the long run • Must develop land-use strategies the recognize short and long-term needs and balance ecosystem services • Important to include land-cover change in forcing scenarios for future climate studies • Reveals the effects humans have on Earth’s climate

21. The Future • Continue developing land-use strategies • Ex: Coffee farms within ~1km of forests benefit from wild pollinators, increasing yields by 20% • Closer collaboration between scientists and practitioners • Ecologists and land-use planners • Climatologists and architects • Find a balance • Between meeting human needs and maintaining ecosystems • Inclusion of land-cover change in future climate models show us that we must take care of our Earth today!

22. Questions?