Theresa May is doing her best to grab some good headlines in the closing weeks of her premiership. Setting a target for net-zero greenhouse gas emissions is vital, but her government’s plans are too little too late.

Theresa May commits to net zero UK carbon emissions by 2050 Read more

Yes, Britain may be the first G7 country to set a net-zero emissions target by 2050, but others have shown greater ambition. Finland committed to be carbon-neutral by 2035, Norway has a 2030 target and eight EU countries have asked for all members of the bloc to commit to net-zero by 2050 and dedicate a quarter of the EU’s next budget to projects fighting climate change. Britain wasn’t among them.

What really matters is action, not words. For all her claims of leadership on climate, May’s record in office has been pitiful: support for fracking (against the wishes of local communities), blocking onshore wind (the cheapest renewable energy source) and displaying unlimited enthusiasm for new roads and runways.

As a result, it’s not surprising that the government’s official adviser, the Committee on Climate Change, has repeatedly warned that the UK is not on track to meet its near-term carbon targets in the 2020s and 2030s.

Legislation will only deliver what’s intended if it is watertight, and this law falls well short. For example, there was no mention of aviation or shipping in the government’s announcement, and it’s not clear if they will be included. Yet aviation is one of the fastest-growing sources of UK emissions, doubling since 1990.

Moreover, there is a very clear “get-out” clause after five years, giving the UK the option of abandoning the target if other countries are not taking similarly ambitious action. The justification for this is that UK industries would face unfair competition if others continued with their carbon emissions.

This is wrong on two counts. It undermines business certainty, which will affect long-term investment decisions. And it fails to give the spur to the UK’s low-carbon sector. The CBI has already said some sectors will need clear pathways to enable investment in low-carbon technologies. This law doesn’t provide them.

But the more egregious loophole is the decision to retain the ability to use international carbon credits to offset Britain’s emissions. This goes directly against the recommendations of the Committee on Climate Change, which said only last month that it was “essential that the commitment [to net-zero] was comprehensive [and] achieved without use of international credits”.

Using international credits allows Britain to carry on emitting greenhouse gases while offsetting those emissions by planting trees in other countries or helping pay for low-carbon energy projects. These things need to happen but they should not be instead of cutting greenhouse gas emissions in the UK, they should be in addition.

The UK cannot claim credit by grabbing the low-hanging fruit of easy wins in the global south, particularly when it slows the rate of decarbonisation in Britain. If we are really serious about net-zero emissions, they must not be achieved with dodgy loopholes and cynical greenwash.

I am also left with the suspicion that, for all the declarations of a climate emergency, the government’s approach is still incremental, based on making green-tinged tweaks to business as usual, in the vain hope that we will somehow creep towards our target of net-zero.

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We won’t. A carbon-free economy must deliver climate justice, focus on deindustrialised communities, provide good quality jobs for workers up and down the country, and support the global south. This law may give us the destination. What really matters is how, and how quickly, we get there.

• Caroline Lucas is the Green party MP for Brighton Pavilion