What is Projected?

1. What is Projected? Bruce A. McCarl Distinguished Professor of Agricultural Economics Texas A&M University mccarl@tamu.edu http://agecon2.tamu.edu/people/faculty/mccarl-bruce/ ClimateChangeAdaptation Energy ClimateChangeEffects ClimateChangeMitigation

2. Where we are Degree of climate change - What is projected Climate models predict increasing emissions will cause a temp increase Source : IPCC AR4t

3. Degree of climate change - What is projected Reto Knutti and Jan Sedlácek, Robustness and uncertainties in the new CMIP5 climate model projections, Nature climate change, 2012, http://www.iac.ethz.ch/people/knuttir/papers/knutti12natcc.pdf

4. Degree of climate change - What is projected • Hotter

5. Degree of climate change - What is projected • Less water Figure 3 j Patterns of precipitation change. Multi-model mean relative precipitation change for two seasons (December–February, DJF, and June–August,JJA) and two 20-year time periods centred around 2025 and 2090, relative to 1986–2005, for CMIP5 (left) and CMIP3 (right). Stippling marks high robustness, hatching marks no significant change and white areas mark inconsistent model responses (see Methods and Supplementary Figs S2 and S3). Texas in relatively severely affected area Reto Knutti and Jan Sedlácek, Robustness and uncertainties in the new CMIP5 climate model projections, Nature climate change, 2012, http://www.iac.ethz.ch/people/knuttir/papers/knutti12natcc.pdf

6. Climate Change is projected to go on Source : U.S. National Assessment

7. Degree of climate change - What is projected • Very likely that heat waves will be more intense, more frequent and longer lasting • Precipitation generally increases but with general decreases in the subtropics • Precipitation intensity is projected to increase but there would be longer periods between rainfall events. • Tendency for drying of mid-continent during summer, indicating a greater risk of droughts in those regions. • Sea level projected to rise 1999 and 2099 by 0.18 to 0.59 m. • Likely increase in hurricane peak wind intensities - an increase in the numbers of the most intense. • Fewer mid-latitude storms- poleward shift of storm tracks • Atlantic Ocean Meridional Overturning Circulation (MOC) – Gulf Stream will slow down

8. So What?

9. Climate Change can be disruptive Source : National Assessment

10. Climate Change can be disruptive Source : IPCC Source : National Assessment

12. What is Projected - sea level http://maps.grida.no/go/graphic/potential_impact_of_sea_level_rise_on_bangladesh http://environment.newscientist.com/channel/earth/mg19526141.600- huge-sea-level-rises-are-coming--unless-we-act-now.html

13. What is Projected - sea level Example 1 Sea Level and hurricanes Adapt Structural protection Abandonment http://yosemite.epa.gov/oar/globalwarming.nsf/content/ResourceCenterPublicationsSLRMapsIndex.html http://www.glo.state.tx.us/coastal/erosion/reimbursement/pdf/Surfside_Beach_historic_shorelines.pdf

14. Types of Effects - National Assessment • Increased warmingAssuming continued growth in world greenhouse gas emissions, the primary climate models used in this Assessment project that temperatures in the US will rise 5-9ºF (3-5ºC) on average in the next 100 years. A wider range of outcomes is possible. • Differing regional impactsClimate change will vary widely across the US. Temperature increases will vary somewhat from one region to the next. Heavy and extreme precipitation events are likely to become more frequent, yet some regions will get drier. The potential impacts of climate change will also vary widely across the nation. • Vulnerable ecosystemsMany ecosystems are highly vulnerable to the projected rate and magnitude of climate change. A few, such as alpine meadows in the Rocky Mountains and some barrier islands, are likely to disappear entirely in some areas. Others, such as forests of the Southeast, are likely to experience major species shifts or break up into a mosaic of grasslands, woodlands, and forests. The goods and services lost through the disappearance or fragmentation of certain ecosystems are likely to be costly or impossible to replace. • Widespread water concernsWater is an issue in every region, but the nature of the vulnerabilities varies. Drought is an important concern in every region. Floods and water quality are concerns in many regions. Snowpack changes are especially important in the West, Pacific Northwest, and Alaska. • Secure food supplyAt the national level, the agriculture sector is likely to be able to adapt to climate change. Overall, US crop productivity is very likely to increase over the next few decades, but the gains will not be uniform across the nation. Falling prices and competitive pressures are very likely to stress some farmers, while benefiting consumers.

15. Types of Effects - National Assessment 6. Near-term increase in forest growthForest productivity is likely to increase over the next several decades in some areas as trees respond to higher carbon dioxide levels. Over the longer term, changes in larger-scale processes such as fire, insects, droughts, and disease will possibly decrease forest productivity. In addition, climate change is likely to cause long-term shifts in forest species, such as sugar maples moving north out of the US. 7. Increased damage in coastal and permafrost areasClimate change and the resulting rise in sea level are likely to exacerbate threats to buildings, roads, powerlines, and other infrastructure in climatically sensitive places. For example, infrastructure damage is related to permafrost melting in Alaska, and to sea-level rise and storm surge in low-lying coastal areas. 8. Adaptation determines health outcomesA range of negative health impacts is possible from climate change, but adaptation is likely to help protect much of the US population. Maintaining our nation's public health and community infrastructure, from water treatment systems to emergency shelters, will be important for minimizing the impacts of water-borne diseases, heat stress, air pollution, extreme weather events, and diseases transmitted by insects, ticks, and rodents. 9. Other stresses magnified by climate changeClimate change will very likely magnify the cumulative impacts of other stresses, such as air and water pollution and habitat destruction due to human development patterns. For some systems, such as coral reefs, the combined effects of climate change and other stresses are very likely to exceed a critical threshold, bringing large, possibly irreversible impacts. 10. Uncertainties remain and surprises are expectedSignificant uncertainties remain in the science underlying regional climate changes and their impacts. Further research would improve understanding and our ability to project societal and ecosystem impacts, and provide the public with additional useful information about options for adaptation. However, it is likely that some aspects and impacts of climate change will be totally unanticipated as complex systems respond to ongoing climate change in unforeseeable ways

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