Global Biophysical Impacts [WP4]
Our analysis addresses the fundamental question of to what degree global mean temperature change is an appropriate indicator for climate change impacts, because biophysical impacts may also be expected to depend on CO2 concentration, changes in precipitation patterns, rate of climate change, and inertia of the biophysical system. Based on projections already generated in a project called ISI-MIP (the Intersectoral Impact Model Intercomparison Project), we are analysing to what degree is the relationship between global warming and biophysical impacts dependent upon the scenario.
We will develop simplified descriptions of changes in renewable water resources, water and carbon fluxes and stocks, and changes in crop yields. We will also create simplified descriptions (called emulators) of the trends in climatic range for ecosystem functioning and focusing on key regions identified from stakeholder dialogue. The resulting descriptions will allow for highly efficient impact projections based on arbitrary temperature and CO2 concentration pathways.
The role of feedbacks from climate change impacts back to the climate system, for example the rate of decomposition of plant material (organic carbon) currently locked within permafrost peatlands and drying of rainforests, will be quantified through a range of tests
Monitoring of present day climate extremes enables us to test impact models against similar conditions to what might become usual at higher-end global warming. We are analysing known changes in crop productivity, river flows and ecosystems with known changes in climate conditions of extreme temperature, precipitation, and CO2 changes.
We are also focusing on evaluating the ability of impact models to take into account effects of extreme events, such as the Amazon drought 2005 and 2010, Russian heatwave of 2010, Western European drought of 2003, US drought of 2011. Current extreme events and their weather data enables us to compare our model output of extreme events with the observed ecosystem relationships such as plant productivity to soil moisture deficit, river discharge to precipitation, crop yields to temperature and precipitation.
Further along in the timing of HELIX we combine the data from WP2 and WP3 to combine our projections of biophysical impacts with the HELIX high resolution climate projections. We are examining improved representations of extremes on river flows, water availability, crop productivity, ecosystems, and coastal flooding. Impacts also depend upon the degree of future adaptation to impacts, not only the climate conditions. We will also analyse adaptation options here, with specific attention to water, agriculture and biodiversity conservation. The conservation data is from the Wallace Initiative database. We will identify refugia where the climate remains suitable for more than 75% of the species currently present, and ‘areas of concern' where climatic suitability disappears for more than 75% of the species currently present. We will then apply this ranking to map the adaptation effort required globally to protect biodiversity.
- To systematically estimate the range of potential biophysical impacts associated with 2°C, 4°C and 6°C, and assess confidence in these estimates; accounting for different possibilities of CO2 concentrations, sea level rise, and time horizons as advised by WP2, and different geographical patterns of climate change across the globe
- To maximise internal consistency between estimates of the global-scale impacts of climate change on glaciers, freshwater supplies, crop productivity, terrestrial biodiversity and flood risk (pluvial, fluvial and coastal) whilst also ensuring high-quality sector-specific information
- To identify selected, coherent biophysical impacts scenarios representing an appropriate (as defined in consultation with stakeholders) range of possible outcomes at each SWL, for use in socio-economic impacts assessment in WP5
Katja Frieler describes this Workpackage (1.5 minute video)