By Gloria Dickie and Simon Jessop LONDON (Reuters) – Corporate plans to slash greenhouse gas emissions fall short of what is needed to combat climate change, with “major credibility gaps” found among the world’s largest companies, according to a new stocktake of net-zero efforts in the public and private sector. Roughly half of the Forbes 2000 largest companies have yet to announce plans to reach net-zero — the point at which greenhouse gas emissions are negated by deep cuts in output as well as methods to absorb atmospheric carbon dioxide. Of the 702 companies with a net-zero target, two-thir…