Climate Change and Pest Risk Analysis – Discussion and Position Papers

1. Climate Change and Pest Risk Analysis – Discussion and Position Papers Prepared by a small TAG and support from IS and PRA Panel members NAPPO 2012

2. Assignment • Prepare a discussion document on the potential for climate change to affect the ability of pests to spread and establish in new areas, including the implications for the current PRA process.

3. Process • Review of climate change literature • Review of WTO disputes regarding pest risk assessment and technical justification for phytosanitary measures • Document sent for peer review by EPPO and Quads

4. An Overview of Climate Change • “Warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global average sea level” (IPCC) • According to model projections, global and regional climate change in this century will be characterized by higher temperatures, altered precipitation regimes and increases in the frequency of extreme events • These will directly affect both human and biological systems, including the ability of pests and invasive species to establish and spread in new ecosystems

5. Some Findings • Global surface temperature increases in 11 of last 12 years • Rising sea levels - decreases in snow and ice • Observed increases in anthropogenic greenhouse gas emissions

6. Temperature Change in North America • In the US, the average temperature has risen more than 1 C over the last 50 years. • In Canada, the average temperature has increased by 1.3 C in the last century with the northwest experiencing the most pronounced increases. • In Mexico, the trend over the last 10 years indicates warming of 0.7 C. • Increases predicted in next 100 years between 1.8-6 C, depending on greenhouse gas emissions.

7. Precipitation Change in North America • In the US, precipitation has increased an average of about five percent in the last 50 years. • In Canada, wet areas are generally getting wetter, dry areas drier, and the probabilities of both heavy rainfall and drought have increased. • Rising sea levels in all of North America. Global sea levels continue to rise, causing flooding and coastal erosion (IPCC 2007).

8. Climate change might affect … • Biodiversity - changes in phenology, population dynamics of native species, geographic ranges, and functioning of ecosystems • Invasive species, causing them to expand into new ranges and affecting the risk associated with them • Warmer temperatures usually increase virulence by promoting growth, reproduction, and higher transmission rates

9. The challenge lies in … • Examining how the changes in climate variables such as temperature, precipitation and increase of atmospheric CO2, as well as extreme events, may impact weeds, insect pests, pathogens and host plants; and • Linking the consequences of climate change for invasive species to the sequential stages of an invasion process: introduction (entry + establishment) and spread.

10. Climate Change Impacts on IS • Entry, establishment, spread • Global change stressors • Uncertainty in climatic and bioclimatic models • Climate change models and PRA – issues of spatial and temporal scale • Fit for purpose: PRA as a decision support tool

11. Climate Change Effects on Entry • Invasive insects or pathogens could be blown into North America via hurricanes from Africa, South America and the Caribbean • Other extreme events such as floods may might result in the ability of previously confined aquatic species to migrate to new areas Larvae of Cactoblastis cactorum Source: Ignacio Baez, USDA The cactus moth (Cactoblastis cactorum) provides an example of facilitated movement by extreme weather events for Mexico. The arrival of the cactus moth is likely attributable to strong winds during the 2005 hurricane season, which transported the insect from host islands in the Caribbean to Mexico

12. Climate Change Effects on Establishment May lead to an increased likelihood of pest establishment through different mechanisms: • Species currently constrained by short growing seasons might be able to set fruit or compete with resident species. • Rising winter temperature may decrease the mortality rate of pathogen populations, increase the pathogen load and consequently increase their range and distribution. Kudzu (Pueraria montana) is an example of an invasive alien plant predicted to undergo range expansion as a result of climate change in North America. It is known in the U.S. as the “plant that ate the south”.

13. Climate Change Effects on Spread Climate change might affect the ability of pests to spread in a variety of ways. For example: • Accelerated spread of vectors, pests and diseases towards the north is predicted for temperate species, as former climate barriers are no longer effective • In a warming climate pests lowland pests may move upwards and threaten mountain ecosystems The mountain pine beetle (Dendroctonus ponderosae) provides an example of a native forest pest that has undergone range expansion due to climate warming, in particular due to less frequent and less extreme cold weather events. Tree mortality caused by Mountain pine beetle in Yellowstone National Park. John W. Schwandt, USDA Forest

14. Fit for Purpose • Intended to help countries decide if a particular organism is a pest, and whether phytosanitary measures should be taken • Process should be transparent, based on sound science, not intended to be an extensive exercise in scientific research for its own sake • Climate and bioclimatic modeling are complex, resource- and time-intensive

15. Legal Considerations • To date, 5 disputes interpreting the role of PRA to justify sanitary and phytosanitary measures have traveled through the WTO dispute settlement process • In each case phytosanitary measures were challenged and were ultimately judged to be in violation of the SPS agreement because of the inadequacy of the risk analysis

16. Dispute Findings • Measures chosen must be based on sufficient scientific evidence that verify necessity • Requirement of rational relationship between the measure and the scientific evidence means such a relationship can only be determined on a case by case basis • Factors to be considered are not intended to be a closed list, so where appropriate, climate change can be taken into consideration with the caveat that there must be an ascertainable risk identified; “theoretical uncertainty is not the kind of risk which is to be assessed” • A PRA must evaluate what is likely or probable – not what is possible • The precautionary principle is not recognized in the SPS Agreement as grounds for justifying measures, precautionary measures can be adopted under certain circumstances as long as these can not be considered arbitrary or unjustified, and accordingly, a disguised barrier to trade • The “rational relationship” requirement means that a decision to include climate change will also be done on a case by case basis, again – based on the sufficiency of the scientific evidence. • An important, but outstanding issue is what constitutes “sufficient”

17. Conclusions • Climate change is occurring and could have significant effects on both biological and human systems, and could impact the ability of IS to spread and establish - possibly resulting in an increased number and severity of invasions • The interaction of climate change with the other pressures involved in global change including trade patterns will increase the need for PRA • A decision to consider climate change scenarios or incorporate complex models into a PRA will depend on feasibility, fit-for-purpose, and the rigor of the associated scientific support • International agreements and jurisprudence indicate that PRA is intended to provide sufficient evidence that a chosen measure(s) is not arbitrary, unjustified, or a disguised barrier to trade • Therefore, climate change projections within a PRA must be sufficiently robust to meet these requirements so the role of climate change in the conduct of PRA will need to be considered on a case-by-case basis

18. Recommendations • The working group recommends that NAPPO: • take a “fit-for-purpose” approach • take into consideration the time and resources available, complexity of the issue, relevance of climate to the phytosanitary issue at hand, and whether or not there is sufficient scientific evidence to show a causal link • consider if the time frame for which the PRA is considered to be “current” should be specified in the document, with an update after a specified amount of time • Include a statement in the PRA about whether or not climate change was considered along with a brief explanation as to why or why not