The European Union has formally submitted its planned contribution to a U.N. climate pact, pledging to cut its greenhouse gas emissions by at least 40 percent by 2030.

The cuts are relative to 1990 levels. The EU's emissions since then are already down by almost 20 percent.

The EU is the second party to submit a climate target to the U.N., after Switzerland. Only a handful of other countries are expected to meet an end-of-March deadline to submit targets.

Others, including India and China are likely going to need more time. All countries are supposed to present targets for a new global climate agreement that governments plan to adopt in Paris in December.

Scientists say rising levels of greenhouse gas emissions are a key driver of global warming.