## Charge Questions

OPP’s Approach

1. OPP is seeking guidance on its approach to climate change to date and suggestions for how to approach future work.
a. Comment on the approach that OPP used to evaluate the models in light of the expected likely effects and impacts of climate change to determine whether climate change would influence the inputs and parameters. b. Of the areas identified as likely to be affected or the effects are uncertain, please offer suggestions as to the likely importance of these factors on risk assessmen t and if likely to be important. C omment on potential approaches to address the uncertainty. 

### Temporal and Spatial Considerations

2. OPP reviews chemicals and assesses risks as needed at least every 15 years. Over a 15 year time period, pesticide use and crop residues from monitoring data could change as a result of climate change.
a. Based on current projections, will the pace of climate change significantly increase the uncertainty in our exposure assessments? b. If yes, which inputs are likel y to change in such a manner that the uncertainty in the exposure assessment would significantly increase? Comment on how OPP might explore this issue.

3. Over time, the environment will change due to climate change and these changes will be manifested differently in different regions of the country. Irrespective of climate change, there already exists a wide variety of climatic conditions across the country. Because climatic conditions greatly vary across the country, often data collected for exposure ass essments are from studies performed at multiple locations chosen to be geographically representative of the entire country.
a. Please comment on the geographic changes anticipated due to climate change relative to the existing climate diversity within the U.S . Over what time period might climate change significantly affect the range of diversity in weather conditions in the U.S in such a way as to significantly increase our uncertainty in pesticide exposure assessments?

### Use of Historic Data

4. All exposure as sessments rely in some degree on historical data

– weather, residues on food, cultural practices, pesticide use practices, etc. In many situations data that are directly used as inputs into an exposure assessment and can readily be updated with each succe ssive assessment. For example, a dietary exposure assessment today would rely on recent monitoring data, while an assessment in 5, 10 or 15 years from now would rely on more up

- to

- date monitoring data than an assessment conducted today. In other situatio ns, data are used to develop a parameter in a model, such as the runoff curve discussed in section III.B.1.e. of the background paper. Please comment on the significance of climate change on the reliability of embedded model parameters. How might OPP systematically approach an evaluation of the significance of such model parameters?

5. Currently, OPP uses weather data from 1960

- 90 in its ecological assessments, giving equal weight to every year. OPP intends to acquire more recent data. Please comment abou t the effects of using these data in light of climate change. If this is viewed as an important factor, will aggregating the data from 1960

- 2010 be appropriate in light of climate change? For example, would the use of data from the last 10 years be a more appropriate indicator of future weather patterns or should OPP consider adding a predictive component to weather data? If the use of predictive models is appropriate, provide any sources of ongoing research or relevant models that might be explored.



### P riority Setting

6. Please consider a systematic approach for OPP to prioritize future work on Climate Change. Priority areas to help guide OPP to inputs/models that would be most important to help assure that our assessments do not underestimate exposure an d risks (include magnitude and uncertainty).