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IBM and 19 other companies have joined Amazon's Climate Pledge, committing to neutralize their carbon emissions, Amazon announced Wednesday. The new signatories include Seattle-based companies MiiR, the upscale thermos manufacturer, and consulting group Slalom.

All told, 53 companies have now signed the Climate Pledge. Members agree to measure and report their , decarbonize their businesses, and purchase offsets to bring their total carbon emissions to zero by 2040, 10 years ahead of the goal set by the Paris Agreement.

Environmental activists, including within Amazon, have said the scope of the climate catastrophe warrants more urgency than a 2040 deadline. Carbon offset programs, meanwhile, are controversial. Some have warned that poorly administered programs provide regulatory and public relations cover for big corporations to keep polluting without actually removing carbon from the atmosphere.

Some Climate Pledge signatories have said they'll act faster than Amazon on . IBM has pledged to zero out its by 2030. Microsoft has said it will be carbon negative by that year, meaning it takes more carbon dioxide out of the atmosphere than it puts in.

The other new signatories of the Climate Pledge are Acciona, Colis Prive, Cranswick, Daabon, Free Now, Generation Investment Management, Green Britain Group, Hotelbeds, Iceland Foods, Interface, Johnson Controls, Ørsted, Prosegur Cash, Prosegur Compañia de Seguridad, S4Capital, UPM and Vanderlande.