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Good afternoon, and welcome to Globe Climate, a newsletter about climate change, environment and resources in Canada.

After two decades doing climate work for NGOs, Steven Guilbeault took a leap into government. This past week, he announced his resignation from politics, and a return to fighting for the environment outside of Parliament. More on that today.

First, let’s catch you up on other news.

1. Pollution: Federal officials took years to notify residents of toxic chemicals in their drinking water
2. Justice: PEI family sues province over ‘forever chemicals’ found in their drinking water
3. Conservation: Federal appeal court upholds First Nations victory to protect wildlife at planned nuclear waste site
4. Food and drink: Facing seafood shortages and price hikes, East Coast chefs eye other fish in the sea
5. Art: At the Vancouver Art Gallery’s climate show, a tough assignment: no preaching allowed
6. Weather: Here’s what Canada’s summer forecast looks like

For this week’s deeper dive, a closer look at a high-profile climate departure from politics.

In today’s letters to the editor, Tom Perry from Vancouver wrote: “In the Liberal Party or the government, who will now advocate for Planet Earth?”

Former Liberal cabinet minister Steven Guilbeault announced his resignation from politics last week, saying he wants to keep up his fight against climate change in other ways. That announcement has put Prime Minister Mark Carney on the defensive once again about the Liberals’ climate change policy.

For example, we reported that climate and energy experts are concerned by the fine print in Ottawa’s pipeline deal with Alberta, and the carbon-pricing system underpinning it. Carney insists that the country’s new climate plan will withstand the test of time amid more demands for changes from the oil and gas sector.

Guilbeault, a career environmentalist, played a key role in many of the previous Liberal government’s climate initiatives now being watered down or straight up reversed by the current government. He plans to resign from his seat later this summer. He quit Carney’s cabinet at the end of last year over the same Ottawa-Alberta energy accord, and issued a scathing letter laying out why he thinks the deal undercuts environmental protections.

In an earlier statement, Carney said the government remains committed to climate action. “We are advancing these missions with the same determination, a new spirit of partnership, and a renewed focus on results.”

Our resident food and farming reporter Kate Helmore attended the opening of Toronto Climate Week this morning, curious about what the Prime Minister’s wife had to say about our changing environment and how Ottawa is reframing the climate file. (Interesting factoid: Diana Fox Carney has a master’s degree in Agricultural Economics). The following quote sums it up:

“Third moral arguments do not get us to where we need to be in a more volatile and uncertain world, where affordability and now security are the dominant concerns. Climate action often falls off or fails to reach the list of priorities. What’s important is to meet people and pools of money where they are, not where we wish they were,” she said.

This opinion is in line with the Prime Minister, who said a gracious goodbye to Guilbeault, mentioning that he has “always been guided by his convictions and driven by his pursuit of a stronger, more inclusive and more sustainable future.”

Guilbeault also said a restrained goodbye to Ottawa, as he spoke from the floor of the House of Commons. He didn’t speak on Carney’s policies, but it was easy to read between the lines.

“The fight for our planet is the struggle of our generation, and I fully intend to keep fighting,” he said.

More from The Globe:

• Shannon Proudfoot: Guilbeault’s resignation and putting water in your climate policy wine
• Campbell Clark: An environmental symbol slips out of Parliament
• The Decibel podcast: A crack in Carney’s Liberal caucus over climate