Three years ago, oil industry spokespeople scoffed when Greenpeace International sent letters to oil companies and their insurers that asked what they would do if oil companies were sued over their history of funding climate denial and opposing policies to fight climate change. The Canadian Association of Petroleum Producers brushed the letters off as a “stunt”, while the Calgary Herald’s editorial board called the comparison to the successful prosecution of Big Tobacco “reckless as well as laughable.”

Laughter turned to silence once the Human Rights Commission of the Philippines launched an investigation into the responsibility of fossil fuel companies for human rights impacts resulting from climate change. Not one of the four Canadian oil companies named in the complaint (CNRL, Encana, Husky, and Suncor) bothered to respond to the investigation, which was launched in 2015 in response to a petition submitted by Filipino disaster survivors and other individuals and supporting organizations (including Greenpeace Southeast Asia-Philippines).

I doubt that anyone is laughing in oil company board rooms now that five California communities, including San Francisco and Oakland, have launched lawsuits against oil companies demanding that the companies help pay for the costs of adapting to climate change-induced sea level rise. Just as Greenpeace predicted in 2014, all five cases are explicitly modelled after tobacco precedent by linking the harms from climate change to companies’ alleged early knowledge of the risks — and their attempts to hinder action to address it.

In launching his city’s case, San Francisco City Attorney Dennis Herrera said: “These fossil fuel companies profited handsomely for decades while knowing they were putting the fate of our cities at risk. Instead of owning up to it, they copied a page from the Big Tobacco playbook. They launched a multi-million dollar disinformation campaign to deny and discredit what was clear even to their own scientists: global warming is real, and their product is a huge part of the problem. Now, the bill has come due. It’s time for these companies to take responsibility for the harms they have caused and are continuing to cause.”

Amongst those being sued in California (albeit not by San Francisco or Oakland) is Canadian oil and gas giant Encana.

It won’t be long before Canadian cities follow suit. Canadian legal researchers have found that tobacco litigation is a powerful precedent for the coming wave of climate lawsuits. Just like in the tobacco cases, these kinds of climate lawsuits may start in the US but they will inevitably spread as the damages mount and the science of attributing specific events to climate change become clearer.

Whether it is Vancouver or Halifax trying to cover the costs of holding back the rising seas or Toronto expanding its stormwater management systems, climate change imposes enormous costs on communities. In Canada, the District of Highlands and the District of Saanich in British Columbia has already sent letters demanding 20 of the world’s largest fossil fuel companies pay their share of infrastructure costs caused by climate change impacts.

This is only fair: these companies have known about these consequences for decades but hid that knowledge so they could continue to profit from selling fossil fuels. They should help pay those costs.

And that’s no laughing matter.