andersen oxford2011

Impacts of climate change on agriculture and ecosystem services:

It's not the planet that needs saving, it's us

Dr. Mark C. Andersen, Professor
Department of Fish, Wildlife, and Conservation Ecology
New Mexico State University
Las Cruces, NM

Oxford Round Table
Climate Change: The Great Matter
Harris Manchester College, Oxford30 March 2011

Image: Gary Halvorsen, Oregon State Archives

Copenhagen committed the world to adaptation

Even if targets are met, there is a substantial gap between impacts that can be mitigated and impacts to which we will have to adapt.Many unavoidable impacts are impacts on ecosystems, includingExtensive coral bleaching

Increased amphibian extinctions

Greatly elevated risk of extinction for many of the world's species

Parry 2010, Nature Reports Climate Change, 4(1002):18-19

What about other impacts that more directly affect humans?

This presentation will ...

Review climate change threats to biodiversity in the context of mass extinctions in the geologic past

Describe climate change impacts on ecosystem servicesHydrologic cycles

Wildfire regimes

Discuss climate change impacts on global food supply Agriculture

Fisheries and aquaculture

Provide some closing thoughts


Describe climate change impacts on ecosystem servicesHydrologic cycles

Wildfire regimes

Discuss climate change impacts on global food supply Agriculture



Climate change threats to biodiversity

Globally, 15% - 37% of species committed to extinction due to climate change alone, not including effects of other factors
(Thomas et al 2004, Nature 427:145 148)

Effects of climate change on biodiversity by year 2100 likely to be exceeded only by effects of land-use changes
(Sala et al . 2000, Science 287:1770-1774)

Comparison of recent and distant past extinction rates with rates at which species are committed to extinction during the 21st century (63). E/MSY is number of extinctions per million species years; Fossil record refers to the extinction rate of mammals in the fossil record (17); 20th century refers to documented extinctions in the 20th centurymammals (upper bound), birds, and amphibians (lower bound) (17); 21st century refers to projections of species committed to extinction according to different global scenarios: vascular plants (38, 18), plants and animals (7), birds (6, 19), and lizards (64). Extinction rate caused by each driver and total extinction rates are discriminated, when possible.(From Sala et al paper)

Mass extinctions in the geologic past

Sepkoski's (1990) Phanerozoic marine family-level diversity curve, with diversity patterns of Evolutionary faunas delineated and representative members of the Paleozoic Fauna illustrated. The stippled area indicates diversity contributed by poorly preserved groups. Cm, Cambrian evolutionary fauna; Pz, Paleozoic Evolutionary Fauna; Md, Modern Evolutionary Fauna. After Sepkoski, 1990

The Big One

End-Permian mass extinction 245 mya
(Erwin 1990, Ann. Rev. Ecol. Syst. 21:69-91)54% of marine families, up to 96% of marine species, lost to extinction

Not as severe for terrestrial ecosystems, but similar

This extinction event coincided with a pronounced spike in atmospheric CO2
(Retallack 2001, Nature, 411: 287-290)

Evolutionary response to past mass extinctions

Early Triassic radiation:Modern patterns of marine biodiversity

Emergence of Mesozoic flora and fauna on landDinosaurs (birds)

Mammals

Modern terrestrial ecosystems (although modern flora completely different)

(Takes millions of years)

Healthy, functioning ecosystems
don't depend on us

We depend on healthy, functioning ecosystems


Describe climate change impacts on ecosystem services

Hydrologic cycles

Wildfire regimes

Discuss climate change impacts on global food supply

Agriculture



Hydrology

Altered annual streamflows

Changes in timing of runoff

Changes in relative length of low-flow and high-flow conditions

Different watersheds differentially vulnerable(Null et al. 2010, PloS ONE 5(4))

Current reservoirs, canals etc. built for current conditions, not future conditions

RESULT:
Changing availability of water for
agricultural and municipal uses

Wildfire regimes will change

10% to 50% increase in fire activity across North America by 2050Effects of fire on vegetation may overshadow direct effects of climate change on distribution, abundance, and dispersal
(Flannigan et al., 2000, Science of the Total Environment, 262:221-229)

Increases in fire frequency in some regions may be balanced out by decrease in othersStill, expect substantial change in global fire regimes
(Krawchuk et al., 2009, PloS ONE 4(4))

Changing fire regimes will impact society

Increases in Fuel load

Ignition rate

Fire intensity

Length of fire season

May overwhelm agency fire response and suppression capabilities
(Podur & Wotton, 2010, Ecol. Modell. 221(9): 1301-1309)

RESULT:
Changing fire regimes will impact both natural and human-dominated landscapes



Hydrologic cycles

Wildfire regimes


Agriculture



Food doesn't come from the store

Agriculture = global food supply

Promising international initiatives

FAO MOSAICC project a modeling tool for assessing impacts of climate change on agricultural production and revenues
(www.fao.org/climatechange/mosaicc/en)

Commission on Sustainable Agriculture and Climate Change Sir John Beddington, Chief Scientist of UK Science Office, findings to be made available by end of 2011
(www.ccafs.cgiar.org/content/commission)

Potential for crop failures

Agriculture throughout Africa runs some risk of negative impacts from climate changeExisting cropping systems and infrastructure not sufficient to meet current demand
(Muller et al., 2011, Proc. Nat. Acad. Sci., 108(11):4313-4315)

Regions with highest food insecurity (South Asia and Southern Africa) face greatest risk of reduced yield and crop failure
(Lobell et al., 2008, Science 319(5863):607-610)

Mechanisms and severity of crop failures

Simulation studies of spring wheat in northeastern ChinaIncreased crop failure rates under future climateThermal stress

Water stress

Maximum failure rates increase more rapidly than median failure rates
(Challinor et al., 2010, Env. Res. Lett. 5(3): 034012)

Mitigating crop failures

Farmers can protect themselves from some of the effects of climate change by planting a more diverse array of crops
(Lin, 2011, BioScience 61(3):183-193)

Even crops thought to be heat-tolerant may be more sensitive to rising temperature than we expect1C temp. increase yield loss in 65% of African maize-growing region
(Lobell et al., 2011, Nature Climate Change, doi:10.1038/nclimate1043)

The impacts are not limited to land-based food production

Impacts on anadromous fishWarmer temperatures

Earlier peak stream flow
(Martins et al., 2011, Global Change Biology, 17(1):99-114)

Impacts on marine fisheriesTemperature

Salinity changes (particularly in coastal fisheries with nearshore/estuarine spawning)
(Lindegren et al., 2010, Proc. Roy Soc. B 277(1691):2121-2130)
(Hare et al., 2010, Ecol. Appl. 20(2):452-464)

There are multiple stressors acting on the global food supply

Human population growth (projected to grow well into this century)

Land-use pressure
(Lambin & Meyfroidt, 2011, Proc. Nat. Acad. Sci., 108(9):3465-3472)

Contribution of nitrogen fertilizer to GHG emissions, unsustainable patterns of nitrogen use
(www.ccafs.cgiar.org/content/commission)

Looming phosphorus shortage
(Carpenter & Bennett, 2011, Environ. Res. Lett. 6:014009)

Crop failures +
growing population +
land-use pressure +
phosphorus shortage =
Potential disaster



Hydrologic cycles

Wildfire regimes


Agriculture



If humanity wishes to preserve a planet similar to that on which civilization developed and to which life on Earth is adapted, CO2 will need to be reduced ...James Hansen

Do we already have all the technology we need?

Amory Lovins: Yes

Breakthrough Institute: No

Does it matter if we don't use the technology we already have?

Our lives and our homes need to be part of the solution

Our lives and our homes need to be part of the solution

Are we worth saving?








Thank you!

References:
http://www.mendeley.com/groups/989481/ort2011environment/

Presentation:
www.slideshare.net, search for Andersen Oxford

andersen oxford2011

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