Original: The memo led to strong Bush administration lobbying, evidently at the behest of ExxonMobil, to oust Robert Watson, a climate scientist, from the IPCC chairmanship, and to have him replaced by Pachauri, who was seen at the time as more mild-mannered and industry-friendly.
Simplified: The Bush administration, at the request of ExxonMobil, wanted rid of Robert Watson, a climate scientist and IPCC chairperson, and to have him replaced by Pachauri, who was seen at the time as more friendly to industry.