cop26's president alok sharma said today that hitting that 1.5 degrees global warming target will be tough and the world needs to come together to achieve it. alexandra mackenzie reports from glasgow. alok sharma, elected president of the 26th session of... the global summit is finally under way. glasgow is hosting world leaders and thousands of delegates for these crucial climate change talks. the president of cop26 told andrew marr that keeping global warming to 1.5 celsius would be challenging. i said if you look at all the commitments that have been made and i said we are heading towards two degrees, how is it that over this next decade and indeed over the next few years, we close that gap so we get closer to 1.5? and that is something that i'm going to try and get broad consensus on at the conference. the swedish teenager greta thunberg arrived in glasgow by train last night. mobbed by fellow activists. she had voiced concern that cop26 would not lead