A suspected cholera outbreak is spreading quickly in war-ravaged Yemen, with an estimated 3,000 to 5,000 new cases every day.
The governor of the Bank of Portugal has called the measures that the European Commission has taken.
Speaking alongside Chinese Premier Li Keqiang, the EU's Donald Tusk said efforts to reduce pollution and combat rising sea levels would now continue without the United States.
Most of the 28 European Union states are IHRA members, but so far, only Austria, Romania and the United Kingdom have formally adopted its definition.
China has been the world's biggest emitter of greenhouse gases stoking global warming since 2007.