British designer Katharine Hamnett has designed a limited edition t-shirt for Climate Week (March 12-18), available exclusively at selected H&M stores nationwide, with 25% of profits going to the Environmental Justice Foundation.

Justin Young and Arni Arnason from The Vaccines are among celebrities backing the campaign and modelling the organic cotton tee, which goes on sale March 12 and carries the Carbon Reduction Label certified by the Carbon Trust.