Tracking water resilience: how a hotter planet could put pressure on our plants

Failure to limit global warming will lead to a less resilient supply of the ‘green water’ that plants and crops need to thrive, according to new climate modelling from the JRC.   Under a ‘high emission’ scenario (where efforts made to reduce greenhouse gases are not successful in limiting warming to 2°C above pre-industrial levels by the end of the century) rainfall will reduce and become more variable in large parts of the world.

Resilient green water supply is characterised by high levels of precipitation and low variability in those levels. In general, these are the most favourable hydrological conditions for crop growth and stable plant ecosystems.

Using six climate models, scientists simulated green water resilience for the historical period 1851-2014 and compared that to expected water resilience over the period of 2015-2100 under a high emission scenario.

The models come from the sixth phase of the Coupled Model Inter-comparison Project (CMIP6) of the Climate Research Programme.

The study projects more than a 40% decline in green water resilience in some region of the tropics, the Mediterranean, South Africa, Australia, and regions of coniferous forests circling the northern hemisphere.

The highest drop in resilience within Europe is projected for Spain, due the decrease of precipitation and the increase of its variability.

Large drops in green water resilience such as the one projected for Spain will challenge the resilience of local ecosystems, and lead to less reliable agricultural production.

The JRC forecast suggests that Scandinavia will also experience a serious decrease in green water resilience, as the increase in the variability of precipitation will be larger than the increase in annual precipitation.

This could also increase flood risk in the region. At the same time, plant resilience in this region may benefit from changes to carbon dioxide and temperature levels.

The results of the study underline the importance of European leadership in pressing for ambitious global climate action to keep global warming below 2°C.

Further information

Annual Green Water Resources and Vegetation Resilience Indicators: Definitions, Mutual Relationships, and Future Climate Projections

 

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