As previously reported on Conduit Street, Rena Steinzor and David Flores argued in a Bay Journal op-ed that climate change effects should be incorporated into the Chesapeake Bay Total Maximum Daily Load (TMDL) target loads that will be used for the development of the Phase III Watershed Implementation Plans (WIPs). The Phase III WIPs must show how each Bay watershed state will meet its target loads for reducing nitrogen, phosphorus, and sediment going into the Bay by 2025.
Recently, the Chesapeake Bay Program Principal Staff Committee decided to delay incorporating climate change into the Bay Model and formal target loads until 2022, although jurisdictions must begin to account for climate change in their Phase III WIPs. Professor and former University of Maryland Center for Environmental Science Donald Boesch supported the Committee’s action in a Bay Journal op-ed (2018-02-14). Boesch, who is a climate change advocate, argued that the Committee’s decision was justified, noting that Bay Program”s computer model data on climate change needs further work, is more accurate in predicting mid-term climate impacts than near-term impacts, and that climate change impacts through 2025 on the Bay are likely to be modest. From the op-ed:
The Bay Program’s computer model estimates of reductions needed to offset the effects of climate change on water quality are, at this point, more exploratory than robust, nor have they been peer-reviewed. Estimates of increased river flows are based on the extrapolation of precipitation trends, and climate model projections of future precipitation vary widely. Unlike weather forecasts, climate models are more reliable for estimating conditions for the mid– and late 21st century, when impacts associated with precipitation, temperature and sea level are expected to increase, than in the near term.
In any case, the Bay Program model currently estimates only a 0.6 percent increase in nitrogen load but a 1 percent decrease in phosphorous load resulting from changing climate between the 1990s and 2025, although nitrate and dissolved phosphate loads might increase by about 2 percent.
Boesch also laid out a broad strategy on Bay TMDL climate change strategies that included: (1) insisting that Bay states be held accountable for meeting their 2025 Bay TMDL goals; (2) implementing climate change-ready best management practices in the stormwater and agricultural sectors; (3) investing in science that will inform smart climate change offset strategies; and (4) having other states follow Maryland’s lead and adopt greenhouse gas reduction targets and the programs needed to achieve those reductions.