The missing Earth system impacts of land-based mitigation

Department of Hydrology and Atmospheric Sciences
12 pm on Wednesday, November 9, 2022
Available remotely via zoom
Contact the department for zoom details or to subscribe to the seminar list
Anna Harper
Senior Lecturer, Climate Science, Department of Mathematics and Statistics, University of Exeter


The majority of low-end climate change scenarios produced by Integrated Assessment Models (IAMs) use land-based CO2 removal to help mitigate climate change. The mitigation is achieved through a combination of bioenergy with carbon capture and storage (BECCS) and reforestation/afforestation. For example, in scenarios consistent with a 2°C target from the IPCC Special Report on 1.5°C, the median CO2 removal from BECCS and Agriculture, Forestry, and other Land Use (AFOLU) was 399 GtCO2 and 110 GtCO2, respectively, by 2100. These mitigation methods required a median land area of 347 Mha and 599 Mha each. Such large-scale land use and land cover change impacts biogeochemical cycles, surface greenhouse gas fluxes, and the surface energy budget. However, an accurate and complete representation of the associated land management practices is absent from the CMIP6 Earth System Models (ESMs).

This talk will focus on these missing processes in ESMs: What are the processes? And what are their impacts on the Earth system? I will focus on recent work to include the representation of bioenergy crops in JULES, which is the land surface model in the UK Earth System Model (UKESM). I will discuss ongoing work to evaluate the biophysical and biogeochemical feedbacks from land-based mitigation, the implications for mitigating climate change, and future scenario development for CMIP.


Anna Harper is a Senior Lecturer in Climate Science at the University of Exeter in the UK. Anna earned a Ph.D. in Atmospheric Science from Colorado State University in 2012, where she studied land-atmosphere interactions in the forests of Amazonia. After moving to Exeter in 2012, she worked on improving the carbon cycle in JULES, the land surface model for the UK Earth System Model (UKESM1), mostly focusing on plant physiology and vegetation responses to drought. From 2015-2020, she served as the Science Committee chair for the JULES model. In 2016, she won an independent research fellowship from the UK Research Council to study the feasibility and impacts of climate mitigation through bioenergy with carbon capture and storage (BECCS). Her research since than has focused on land-based climate mitigation.