Michal Kurtyka, the Polish official who led U.N. climate change negotiations in Katowice, Poland. On Dec. 15., nearly 200 countries agreed to a set of rules that will implement the landmark Paris agreement.

Michal Kurtyka, the Polish official who led U.N. climate change negotiations in Katowice, Poland. On Dec. 15., nearly 200 countries agreed to a set of rules that will implement the landmark Paris agreement.