* First carbon offset futures contracts to launch within weeks
* Over-the-counter market is unregulated, small, opaque
* Critics fear race to bottom
* For factbox on carbon offsets, please click on
LONDON, Feb 25 (Reuters) - An expected dash by big corporations for offsets to meet their climate targets has prompted financial exchanges to launch carbon futures contracts to capitalise on what could be a multi-billion dollar market.
It’s a step change. Carbon offsets, generated by emissions reduction projects, such as tree planting or shifts to less polluting fuels, have struggled for years to gain credibility, but as climate action has become urgent, their market is expected to grow to as much as $50 billion by 2030.