A JRC paper published in Scientific Reports today proposes a new risk assessment approach that takes account of the impacts of concurrent climate extremes.
This new method, which can be applied to assess the combined effect of climate extremes on a wide range of areas, is applied to large-scale heat stress and drought events that occurred in the key wheat-producing areas of the world in recent decades, in order to identify regions where concurrent climate extremes are likely to occur in the future.
Effects of concurrent climate extremes
To date, most studies that analyse the effect of extreme climate events at the global scale have focused on a single type of event, without considering how one can influence the occurrence of others.
Concurrent climate extremes pose a serious threat to key socio-economic sectors which are highly interconnected at the global scale, such as agriculture. As their impacts can trigger price shocks and market volatility (thereby destabilising the global food market), it is essential to understand how these events will impact key crop-producing regions of the world.
While one-off extreme events can often be absorbed and overcome, concurrent events can trigger longer-term negative effects. This is the case of global wheat production.
Most wheat (one of the world’s most important crops) production is concentrated in eight regions of the world –Australia, Canada, China, India, Russia, Ukraine, USA and the EU.
Events such as drought, heat stress and water excess can cause large wheat yield losses and thus have serious socio-economic impacts, especially if they occur in several producing regions within a relatively short period of time.
The findings of the study
To achieve a better understanding of concurrent extremes, the authors have developed and used an innovative approach to investigate the effects on wheat production of two types of extreme weather events - large-scale heat stress and drought - that have occurred in the eight key wheat-producing regions of the world between 1980 and 2010.
They analyse the dependence of both heat stress and drought events within each of the eight regions, and the interdependence among different regions. The results indicate the probability of a region experiencing heat stress/drought events when one has already occurred in that region, and of a heat stress/drought event occurring in a region when one has already occurred in another.
Two groups of clear dependence structures emerged, one linking the three main producers (EU, China and India) and the other composed of the remaining five countries. Heat stress in China seems to aggravate events’ occurrence in India and vice versa, whereas events in the EU and India seem to inhibit each other. The study found a lower degree of interdependence of drought events.
The authors recommend that global impact assessments of agricultural markets should integrate the interdependencies of different regions of the world, in order to accurately assess exposure and vulnerability to climate extremes.
By taking concurrent extremes into account, risk assessments (especially those linked to climate change) are more robust and reliable, and less likely to underestimate climate risks.
This is particularly important given the current changing climate context, characterised by an intensification of these extremes and expected rapid population growth.
- 3 April 2019