BERLIN (AP) — Diplomats and environmentalists are gathering in Bonn, Germany, to keep working on the rules governing the Paris climate accord.

The talks starting Monday are part of preparations for December's global climate summit in Katowice, Poland, when the so-called Paris rulebook must be formally approved.

Among the unresolved issues are how to ensure transparent monitoring of what countries do to cut global emissions and the methods used take stock of what countries have achieved.

Advocates also want governments at the two-week talks to explicitly acknowledge that current national pledges won't be enough to keep global warming below 2 degrees Celsius by 2100, and therefore raise their ambitions.

While U.S. President Donald Trump has threatened to pull out of the 2015 Paris accord, the rest of the world remains committed to the deal.