The Virgin Earth Challenge was a competition offering a $25 million prize for whoever could demonstrate a commercially viable design which results in the permanent removal of greenhouse gases out of the Earth's atmosphere to contribute materially in global warming avoidance. The prize was conceived by Richard Branson, and was announced in London on 9 February 2007 by Branson and former US Vice President Al Gore. Among more than 2600 applications, 11 finalists were announced on 2 November 2011. These were Biochar Solutions, from the US; Biorecro, Sweden; Black Carbon, Denmark; Carbon Engineering, Canada; Climeworks, Switzerland; COAWAY, US; Full Circle Biochar, US; Global Thermostat, US; Kilimanjaro Energy, US; Smartstones – Olivine Foundation, Netherlands, and The Savory Institute, US. The prize was never awarded. In 2019, Virgin took the prize website offline after having kept the 11 finalists in suspension for eight years. Al Gore had withdrawn from the jury earlier and commented that he was not part of the decision to discontinue the contest. The challenge The Prize was to be awarded to "a commercially viable design which, achieves or appears capable of achieving the net removal of significant volumes of anthropogenic, atmospheric GHGs each year for at least 10 years", with significant volumes specified as "should be scalable to a significant size in order to meet the informal removal target of 1 billion tonnes of carbon-equivalent per year". One tonne of carbon-equivalent (C) equals 3.67 tonnes of carbon dioxide (). (Because of the relationship between their atomic weights, more precisely 44/12.) At present, fossil fuel emissions are around 6.3 gigatons of carbon. The prize would initially only be open for five years, with ideas assessed by a panel of judges including Richard Branson, Al Gore and Crispin Tickell (British diplomat), as well as scientists James E. Hansen, James Lovelock and Tim Flannery. The prize term was extended until 2019. Around two hundred billion metric tons of carbon dioxide have accumulated in the atmosphere since the beginning of the industrial revolution, raising concentrations by more than 100 parts per million (ppm), from 280 to more than 380 ppm. The Virgin Earth Challenge was intended to inspire inventors to find ways of bringing that back down again to avoid the dangerous levels of global warming and sea level rise predicted by organisations such as the Intergovernmental Panel on Climate Change. The Virgin Earth Challenge was similar in concept to other high