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 assessment and if likely to be important. 

Comment 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 likely 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 assessments 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 assessments 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 successive 

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 situations, 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 about 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. 

Priority 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 and risks (include magnitude and 

uncertainty).