Forewarned is forearmed
by Anna Freeman
The weather conditions prevailing in an area over a long period of time influence nearly every aspect of our lives and present both a resource and a hazard. Seasonal temperature cycles conditioning crop growth and energy demands are known as ‘climate resource’, while hot spells, floods and droughts are examples of ‘climate hazards’. More hazardous events and the variation in climate resource are known as climate risks. You have probably heard of wildfires in Australia and Siberia, heatwaves in Europe and floods in Britain, and the image of just how dangerous some climate risks could be is clear.
Measure the risk
Climate change might alter the magnitude, duration, frequency, timing, and spatial extent of events, all of which could be challenging. We can use these to measure climate risk. ‘Magnitude’, for instance, can be an extreme value over several years. ‘Duration’ defines how long an event lasts or how long conditions are within a specific range – such as the duration of the growing season. ‘Timing’ tells us when something occurs, and ‘frequency’ defines how often an event occurs. For example, heatwaves can be calculated as numbers of events per year (‘magnitude’) or number of days per year (‘duration’).
Then we need to consider the ‘exposure’ – the livelihoods, assets, and ecosystems that could be negatively affected by hazard or change in climate resource – plus our ‘vulnerability’ to suffering harm or loss.
Climate risks could be presented as future impacts, but to do this we really need to assume how the economy adapts to climate change. Another approach is to calculate a series of climate risk indicators, which relate to, but do not measure the socio-economic impact. I’m currently working on a project, led by Prof. Nigel Arnell and Dr. Alison L Kay, identifying and estimating these indicators for the UK.
Indicators
The project has identified several indicators relevant to climate risks
- Health and well-being indicators relate to ‘Met Office heatwave’ and the NHS ‘amber alert’ temperature thresholds.
- Energy indicators are proxies for heating and cooling energy demand, based on thresholds used in building management.
- Transport indicators are based on thresholds leading to increased operational risks of road surface melting or failure of railway track and signalling equipment etc.
- Agri-climate indicators are proxies for agricultural productivity.
- Drought indicator is expressed as the proportion of time in ‘drought’.
- Wildfire indicators are based on fire warning systems currently used by the Met Office.
- Water indicators are proxies for the effect of climate change on river flood risk and on water resource drought.
Projections – 100 years ahead
The Met Office UK Climate Projections (UKCP) describe how the UK’s climate might change over the 21st century over the UK. The new UKCP18 projections (Lowe et al., 2018) combine results from the most plausible climate models at 60km, 25km, 12km and even 1km grid resolution over the country. In our study, we applied the UKCP18 changes in climate to the observed 1981-2010 baseline climatology (Met Office, 2018) to produce a series of projections of future climate, and we calculated our climate risk indicators.
Initial results
Figure 1: Indicators for transport, agriculture, and wildfire (MOFSI – The Met Office’s Fire Severity Index) between 1981-2100 estimated as 30-year mean. These are worst case scenario (high emissions) risks.
Figure 1 shows that in the worst-case scenario (high carbon emissions) climate risks for transport, agriculture, and wildfire will increase across the country. This is also true for public health, floods, and droughts. Demand for cooling energy will increase, but demand for heating energy will decline. The warmer southern and eastern England will see more heat extremes, but the rate of warming may be greater further north and west.
Bad news: If we don’t reduce carbon emissions in the atmosphere, we will follow the high emission scenario and face dangerous climate risks. Good news: by reducing emission, nationally and globally, the risks can be reduced, and by understanding how risks are changing we can develop adaptation and resilience strategies to lessen the impacts of climate change. For you and me this means that the severity of climate risks rests in the hands of humanity.
For more in-depth results please follow the University of Reading’s news updates. If you want to know more about the climate risks project, please email: dr.anna.freeman@gmail.com
References:
Lowe, J.A. et al. (2018) UKCP18 Science Overview Report. Met Office Hadley Centre, version 2.0 https://www.metoffice.gov.uk/pub/data/weather/uk/ukcp18/science-reports/UKCP18-Overview-report.pdf
Met Office (2018) HadUK-Grid Gridded Climate Observations on a 12km grid over the UK for 1862-2017. Centre for Environmental Data Analysis, 15/07/2019. http://catalogue.ceda.ac.uk/uuid/dc2ef1e4f10144f29591c21051d99d39