We are scientists recently arrested in Canada for blockading a 125-car train carrying coal destined to release 26,000 tonnes of carbon dioxide into the atmosphere. We joined 11 other Canadians in this act, despite the personal risks and potential negative impact on our careers.

Time is running short and our dialogues on climate change with Canada's conservative government have been futile, which is why we undertook this extreme action. We were following the example of NASA climatologist James Hansen, who has been arrested three times in the past three years for civil disobedience in protesting against the mining of coal or development of the Canadian oil sands.

If the rate of carbon emissions does not decrease soon, the 2°C threshold for serious consequences of climate change could be broken this century (M. New et al. Phil. Trans. R. Soc. A 369, 6–19; 2011). Yet many nations, including Canada and the United States, remain more concerned with building infrastructure to extract and transport fossil fuels than with seeking alternative energy solutions.

Civil disobedience has a long-standing tradition of inducing social change when those in power fail to act. Governments are neglecting their responsibility to future generations. Because science is built on professionalism and objective evidence, media coverage of our arrests will ensure that they, and the voting public, receive a forceful message.