In an unusual, “landmark” ruling, the German constitutional court has found that the country’s greenhouse gas emissions reduction target for 2030 is too low because it places an excessive burden on future generations to reduce emissions. In addition, the court found that government planning was too vague about what measures would need to be taken after 2030 to achieve the net-zero 2050 target. A spokesperson for Chancellor Angela Merkel described the court ruling as “pioneering”, and in response, the federal government is to set new targets, with a 65% greenhouse gas emissions reduction target to be applicable for 2030 (up from 55%), and then an 88% target for 2040 and a 100% (net) target five years earlier than previously planned, at 2045. By the end of 2020 (including a pandemic-induced fall), German emissions were 40.8% lower than reference 1990 levels, meaning that a further 24.2% from 1990 levels need to be achieved over the next nine years, or relative to 2020 emissions, a 40% fall is required. This will be a mammoth task (as the news from Japan this week suggests), one that will deeply challenge scientists and engineers, but also society more widely. It will be an incredible achievement if the goal is achieved, though many will ask at what cost.