Allegra Stratton, former Downing Street press secretary, has faced criticism for saying people could make a difference by not rinsing their plates before putting them in the dishwasher.
She told The Independent joining the Greens was another one of the ways Britons could help protect the planet from rising carbon emissions.
Asked why she thought other parties and organisations like the Green Party or Greenpeace were critical of her advice, she said: “When people say to me, ‘What can they do?’, they can do many things, they can join Greenpeace, they can join the Green Party, they can join the Tory party.”
Ms Stratton added: “So there’s lots of ways they can get involved in politics, but for those people who wouldn’t [do that], how do you start to change your life in manageable, achievable, feasible, small ways?”
Green Party co-leader Jonathan Bartley responded to her comments by saying: “After decades of inaction from both the Conservatives and Labour, we would absolutely agree with the government that joining the Green Party is the best thing people can do to help tackle climate change.”
He added: “As we witness the Conservatives waste time talking about loading dishwashers and fantasy projects such as Jet Zero, it is reassuring to see that they do understand it is only the Greens who can bring about the real change that is needed if we are to prevent climate catastrophe.”
Molly Scott Cato, former Green MEP and economic spokesperson for the party, added: “When [Ms Stratton] said people could make a difference by joining the Green Party, she wasn’t wrong.”
Ms Stratton has faced considerable flak over her recent article in The Telegraph, in which she suggested that “micro-steps” such as not rinsing dishes before putting them in the dishwasher would help tackle the climate crisis.
Defending her article, the COP26 summit spokesperson said: “I was trying to connect with people who – my understanding is – feel that it’s too much and too overwhelming to process.
“You will have a net-zero strategy from us before Cop26. You’ll have a series of strategies from us in the next few months. We are doing the heavy lifting. What I’m trying to do is speak to people who may not be doing anything.”
She added: “We’re busting a gut to make Cop26, which is the last best chance to tackle runaway climate change, deliver the change that all of us need.”
Ms Stratton also suggested that consumers might buy shower gel in bar form, packaged in cardboard, and could consider walking rather than driving to the shops as part of the “micro-steps”.
Labour MP Luke Pollard, the shadow environment secretary, claimed the suggestions showed a lack of ambition and said it was time for “proper leadership” from the government.
He told The Independent: “The planet is on fire and we are living in a climate and ecological emergency. If the government’s best answer is rinsing dishes, we are in serious trouble.”
Doug Parr, policy director at Greenpeace UK, said Ms Stratton’s suggestions of “micro-steps” could be seen as “displacement activities”, instead of outlining the big changes required.
He said: “Whilst one should not belittle individual efforts to help tackle the climate crisis, not rinsing plates and freezing bread is about as useful as a chocolate teapot when it comes to the enormity of the challenge that it presents.”