We won’t pretend to be wildly interested or highly knowledgeable about how BlackRock manages its investments, but its letter to clients this week makes it abundantly clear that it is going through a step change in investment strategy, putting sustainability where traditional market cap-weighted index exposures once were. With BlackRock understood to manage some $7 trillion in assets, its adherence to the sustainability standards which the IPCC says are compatible with 2 degrees of warming, will make a huge difference to the availability of funds for companies under risk from climate change. It could effectively starve them of investment. BlackRock, in a letter to clients, out this week highlighted coal as a market it could no longer invest in, where…