Almost all work to date on stratospheric sulfate injection has been limited to modeling and laboratory work.[citation needed] In 2009, a Russian team tested aerosol formation in the lower troposphere using helicopters.[131] In 2015, David Keith and Gernot Wagner described a potential field experiment, the Stratospheric Controlled Perturbation Experiment (SCoPEx), using stratospheric calcium carbonate[132] injection,[133] but as of October 2020 the time and place had not yet been determined.[134][135] SCoPEx is in part funded by Bill Gates.[136][137] Sir David King, a former chief scientific adviser to the government of the United Kingdom, stated that SCoPEX and Gates' plans to dim the sun with calcium carbonate could have disastrous effects.