LONDON, March 29 (Reuters) - British insurer and asset manager M&G will allow shareholders a vote on its climate plans at its 2022 annual general meeting, it said on Monday. Ahead of the 2022 AGM, M&G said it will provide investors its roadmap to previously announced targets to reduce carbon emissions from its own operations to net zero by 2030, and from its internal and external investment portfolios by 2050, in line with the goals of the Paris Agreement.