Dongfeng has led a few projects involving large-scale international collaborations to assess the impact of modern climate change on physical landscapes and hydropower systems. His collaborators include many well-known geomorphologists and cryosphere scientists such as Xixi Lu, Des Walling, Jaia Syvitski, Irina Overeem, Albert Kettner, Stuart Lane, Amy East, Achim Beylich, Bodo Bookhagen, Bob Wasson, Michèle Koppes, Dan Shugar, Stephan Harrison, Walter Immerzeel, Tobias Bolch, Nepal Santosh, Jakob Steiner, Yong Nie, IAG DENUCHANGE working group, and Cuomo Foundation, etc. His major scientific achievements can be summarized as below:
(1) Sediment yields and the sensitivity of river sediment loads to climate change in High Mountain Asia (HMA). Dongfeng led an international team (Irina Overeem, Des Walling, Jaia Syvitski, Albert Kettner, Bodo Bookhagen, Ting Zhang, Yinjun Zhou and Xixi Lu) and for the first time quantitatively estimated the sensitivity of sediment loads to changes in temperature and precipitation for 28 rivers in HMA and projected their future changes by 2050. This work, published in Science in October 2021 and widely reported by major scientific news outlets (e.g., Scientific American, EurekAlert, Science Daily, etc.), provides the robust evidence of the impacts of modern climate change on landscape change and fluvial sediment fluxes. The substantially increase sediment fluxes in response to a warmer and wetter HMA have important implications for the securities of region’s energy-food-environment. (Li et al., 2021, Science)
(2) Mountain landscape instability and sustainable hydropower systems in a changing climate. Dongfeng led an international team (Des Walling, Tobias Bolch, Bob Wasson, Stephan Harrison, Michèle Koppes, Stuart Lane, Dan Shugar, Santosh Nepal, Jakob Steiner, Walter Immerzeel, …, Ting Zhang, and Xixi Lu) and identified a range of climate-driven mountain landscape instabilities including glacial retreat and detachments, permafrost thaw and associated landslides, rock-ice avalanches, debris flows, outburst floods from glacial lakes and landslide-dammed lakes, increased erosion and sediment fluxes in HMA. It also discussed the negative impacts of these interacting cryospheric hazards on hydropower systems and recommended forward-looking design and maintenance measures and sustainable sediment management solutions that can help transition towards climate change-resilient dams and reservoirs in HMA, in large part based on improved monitoring and prediction of compound and cascading hazards (Li et al., 2022, Nature Geoscience)
(3) Sediment sources, dynamics and modelling in permafrost river basins.
- Dongfeng and colleagues developed an attribution framework and quantified the relative impacts of temperature increase and precipitation variation on the increasing water and sediment fluxes in a cryospheric headwater basin on the Tibetan Plateau (Li et al., 2020, GRL)
- Dongfeng and colleagues identified the major runoff regimes and sediment sources for permafrost basins and introduced a concept of ‘mountain erodible landscapes’ to denote the most relevant landscapes (e.g., active glaciers, permafrost slopes, and fluvial channels) that contribute runoff and sediment processes within a cold mountainous catchment. A proxy, active contributing drainage area (ACDA), is also proposed to quantify the seasonal dynamics of erodible landscapes (Li et al., 2021, WRR ; Zhang and Li et al., 2022, HP)
- Dongfeng and colleagues also explained the time-varying sediment-discharge relationships across seasons using the theory of permafrost active layer freeze-thaw cycle and co-developed a model (Sediment-Availability-transport; SAT model) to simulate the dynamic time-varying sediment-discharge relationships in permafrost rivers. (Li et al., 2020, GRL; Li et al., 2021, WRR; Zhang and Li et al., 2021, WRR)
(4) Disentangling the impacts of climate change and multiple human activities on sediment transport. Dongfeng and colleagues developed the ‘multiple-double-mass-curves’ framework to disentangle the impacts of climate change, land-use change, and damming on changes in catchment-scale sediment fluxes in the human-impacted Jinsha River and Jialing River of the upper Yangtze. (Li et al., 2018, Geomorphology; Zhou and Li et al., Catena)
(5) Downstream geomorphic impacts of large dams. Dongfeng and colleagues assessed the impacts of the operation of the big dams in the Yangtze River on downstream fluvial processes (channel incision, mid-channel bar shrinkage, and planform shift) and discussed their implications for water supply, flood control, and waterway navigation (Li et al., 2019, ESPL ; Hu and Li et al., 2022, WRR; Xu et al., 2016; Yang et al., STOEN, Yang et al., 2022).