Climate crisis: Countries’ vague net zero claims ‘could compromise Paris agreement’, scientists warn

The race to “net zero” is on. By the middle of the century 126 countries have said they will have brought their overall greenhouse gas emissions down and will offset the rest, in news which has been widely welcomed by climate campaigners.

There’s just one hitch: what does net zero mean, and how much offsetting might be required or can be done?

This lack of a consensus, alongside a lack of transparency over what countries and institutions mean when they say they’ll hit “net zero”, scientists have warned.

Writing in the journal Nature, a team of scientists from Imperial College London, the German Institute for International and Security Affairs, the University of New England in Australia and the Australian National University said: “Vague claims by countries and companies will lull the world into missing its climate goal.”

They write: “Plans are hard to compare, and definitions loose. The details behind ‘net-zero’ labels differ enormously. Some targets focus solely on carbon dioxide. Others cover all greenhouse gases. Companies might consider only emissions under their direct control, or include those from their supply chains and from the use or disposal of their products.

“Sometimes the targets do not aim to reduce emissions, but compensate for them with offsets.”

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As the impacts of the worsening climate crisis become increasingly evident, “the stakes are too high” for vague announcements, they said.

As a result, the group of scientists has set out how the ambiguities around what net zero means might be addressed.

They set out three key aspects of net zero goals which require clarification. These are: the overall scope of each net zero plan, how these plans are considered adequate to tackle the problems and are fair for the country or institution putting them into practice, and what they described as “concrete road maps towards and beyond net zero”.

The researchers said the UN’s Cop26 international climate summit in Glasgow in November represents a major opportunity to bring clarity to what net zero really means.

At the summit, countries will present new climate pledges, therefore agreeing a net zero framework will ensure transparency and certainty as to what can be achieved.

The authors also emphasised the necessity of viewing net zero targets as just a waypoint on the journey to lowering global greenhouse gas emissions beyond net zero.

They said: “Net zero targets are not end points. They are themselves milestones to meeting net-negative emissions targets further down the road.”

Their analysis includes a “checklist for rigorous and clear net zero plans”.

These are:

Scope

• What global temperature goal does this plan contribute to?

• What is the target date for net zero?

• Which greenhouse gases are considered?

• How are greenhouse gases aggregated?

• What is the extent of the emissions (over which territories, time frames or activities)?

• What are the relative contributions of reductions, removals and offsets?

• How will risks be managed around removals and offsets?

Fairness

• What principles are being applied?

• Would the global climate goal be achieved if everyone did this?

• What are the consequences for others if these principles are applied universally?

• How will your target affect others’ capacity to achieve net zero, and their pursuit of other Sustainable Development Goals?

Road map

• What milestones and policies will support achievement?

• What monitoring and review system will be used to assess progress and revise the target?

• Will net zero be maintained, or is it a step towards net negative?

The article is published in the journal Nature.