BERLIN (AP) — Officials from around the globe are beginning three weeks of grueling climate talks. They will involve grappling with a number of thorny climate and political issues, without the benefit of face-to-face meetings, due to pandemic restrictions. The U.N. climate office in Bonn, Germany, has designed a schedule of virtual sessions that will see negotiators share the burden of joining meetings before dawn, during the afternoon or late at night — depending on their respective time zones. Progress at the talks is seen as key to a successful U.N. climate summit in Glasgow, Scotland, in November. But due to concerns about the format, no official decisions are expected at the virtual talks May 31 to June 17.