17 August 2023
Natural hazards for nature-based carbon
Dr Niels Andela
Head of Remote Sensing
Dr Dave van Wees
Remote Sensing Scientist
Carbon projects are exposed to a range of natural hazards, from fire and drought, to sea level rise, pests and diseases. BeZero combines near real-time monitoring and long-term satellite time series of disturbance mechanisms and impacts, to assess risks to carbon efficacy for all nature based projects.
These assessments inform our view of non-permanence risk, as well as over-crediting and leakage risks associated with accurate reporting of disturbance events. Our opinion on the efficacy of carbon credits depends on how reliably past emissions are accounted for, and on the project mitigations in place to counter future risk through buffer pools or interventions on the ground.
Carbon emissions resulting from natural hazards vary with the area affected and the severity of ecosystem impacts. For instance, drought can affect large areas but generally results in modest carbon emissions per unit area, whereas fire impacts are more concentrated and severe. Interactions between different natural hazards, like drought and fire, are often complex, modified by human land use, and single events can manifest as both short-term (direct) and long-term (committed) emissions.
We source information on fire, climate, and sea level rise from space agencies, national research institutes, and academic labs. For example, our assessment of drought risk begins with a summary of climatological conditions across the project area and surrounding landscapes. This encompasses both long-term averages mapped at c. 1 km spatial resolution, and times-series of intra- and inter-annual variation mapped at c. 10 km resolution. Using long-term records of precipitation and temperature from the ECMWF together with soils data from ISRIC, we construct drought indices to understand how drought-stress on vegetation and soils is changing over time. These indices stretch back to the 1980s (when data from weather satellites became more reliable) and we update them annually.
For some ecosystems, we observe a close relationship between drought and fire. We assess the extent of fire disturbance using a record of satellite-derived burned areas from NASA spanning more than two decades. Active fire detections, or ‘hot pixels’, observed by the latest generation of thermal instruments, provide near-real time context on carbon combustion and complementary detections of fires as small as 1 ha, including those in the forest understory.
Damage from drought and wildfires can also increase the vulnerability of vegetation to pests and diseases (and vice versa), especially in contiguous areas with low species diversity, as is common for managed forests in the IFM and ARR subsectors. Our Ratings team reviews literature on the spatial distribution of common pests and diseases relevant to planted species, and we take a holistic view of these risks given planting patterns and project activities.
Learn more about Geospatial & Earth Observation at BeZero