After dithering for decades, governments finally seem to be paying serious attention to the problem of global climate change. Late last year, at the Paris climate conference, they adopted a major new agreement to limit global warming, beginning a process to strengthen commitments to reduce greenhouse gas emissions over time. For many observers, the promises of the Paris conference offer too little, too late, because emissions are high and still rising and because there will be major disruptions to the climate even if countries meet their emissions-reduction pledges. Nevertheless, it had been 18 years since the world’s governments left a major climate summit with an agreement in hand, so just getting to yes in Paris has offered climate diplomacy fresh credibility.
Until now, governments have focused on limiting the greenhouse gases that cause global warming and its attendant hazards, such as rising sea levels and stronger storms. But there is