Sim­u­lat­ing the future

Researcher Andrew Leakey is sim­u­lat­ing atmos­pher­ic con­di­tions for the next half of the cen­tu­ry. The data obtained is sup­posed to mit­i­gate the con­se­quences of cli­mate change.

Send­ing soy­bean plants into the future to study their response to cli­mate change. This is the basic idea behind Andrew Leakey’s exper­i­ment. “If you look at the lit­er­a­ture from the past 30 years, the con­clu­sion is almost always the same: The rise in CO2 will improve soy­bean yields.” The Amer­i­can researcher wants to deter­mine whether this is true in prac­tice in a so-called FACE facil­i­ty. “FACE” stands for Free Air CO2 Enrich­ment. With this method, gas is released from noz­zles which react to changes in wind speed and direc­tion. This makes it pos­si­ble to sim­u­late atmos­pher­ic con­di­tions like­ly in 2050 on test plots.

Andrew Leakey is a researcher at the Uni­ver­si­ty of Illi­nois, USA.

In the first four rainy years of the exper­i­ment, CO2 did actu­al­ly boost pro­duc­tion. In the fol­low­ing dry year, how­ev­er, the fer­til­i­sa­tion effect became a dou­ble-edged sword. “More car­bon diox­ide in ear­ly growth stages, when water is avail­able, means more pho­to­syn­the­sis. When it gets dri­er lat­er, how­ev­er, more water is need­ed because of the larg­er leaf sur­face.” And this in turn led to a drop in yields. The find­ings sug­gest that yield declines in the Amer­i­can Mid­west could take place ear­ly on.

If you look at the lit­er­a­ture from the past 30 years, the con­clu­sion is almost always the same: The rise in CO2 will improve soy­bean yields.

Andrew Leakey

At the end of 2018, a study sum­marised the results of the 32 FACE facil­i­ties world­wide. While yields drop the clos­er you are to the equa­tor, in north­ern lat­i­tudes soy­beans, maize or wheat could ben­e­fit from the rise in CO2. “In some areas of Great Britain, for exam­ple, improve­ments in yields are like­ly to occur.”

How­ev­er, in regions bad­ly affect­ed by cli­mate change these neg­a­tive effects may be mit­i­gat­ed. “On the pos­i­tive side we  now know the reac­tion mech­a­nisms of soy­beans,” says Mr Leakey. The exper­i­ment will con­tin­ue, since more data is urgent­ly need­ed. Farm­ers and agron­o­mists need to bet­ter under­stand such mech­a­nisms in order to devel­op vari­eties or cultivation prac­tices that coun­ter­act the expect­ed decline in yield. There is a lot at stake for Amer­i­can soy­bean farm­ers, Mr Leakey recalls: “One third of the world’s sup­ply of soy­beans is pro­duced here in the Mid­west.”