I don't think Corbyn's proven his case. He doesn't reveal his methods so no other scientist can offer an assessment of them, the Wikipedia piece about him records times when he's been wrong about major weather events, he makes predictions a year in advance and modifies them as time goes by so whatever happens he'll probably be able to point to a time when he said it would, and I couldn't find an analysis of his predictions versus what actually happened. The only things I could find were so hedged about with caveats and conditional clauses I couldn't conclude anything from them but the obvious, sometimes he's right and sometimes he's wrong, like any forecaster. And a subject line like "It's the sun, stupid" is not conducive to reasoned debate, credibility takes a hit right off the top.