ClientEarth Q&A: What makes a climate legal case?

ClientEarth’s head of litigation Gillian Lobo tells edie about how the organisation decides which climate cases to bring forward and what the litigation landscape will look like for the rest of the year.

ClientEarth Q&A: What makes a climate legal case?

Judge Clive Sheldon ruled in favour of four of the five grounds presented in the legal challenge.

  • How do environmental lawyers choose which cases to bring?

We at ClientEarth work to create systemic change for nature and people, from stopping fossil fuel pollution to cleaning up the air we breathe, from calling out greenwashing to protecting biodiversity and gaining access to justice for citizens. Due to the broad range of areas we work on, we’re disciplined in how we identify and pursue interventions, and so we rigorously assess our external context including environmental science, technology and data, as well as global legal and geopolitical trends. The starting point is however always the law.

  • What is the process for furthering these cases?

It really is on a case-by-case basis, but we always undertake careful analysis of the relevant law, legal procedure, facts, science and evidence.

If we are satisfied that there are grounds to bring a claim we will prepare the case by collating our factual and expert evidence, developing our legal arguments and engaging external legal, scientific and technical experts, Prior to filing the case we will write to the proposed defendant to see whether the case can be resolved without litigation, which is the best outcome for everyone. If this is not possible, we prepare the court papers for filing.

  • How do cases differ when filed against private sector entities vs against public authorities?

The specific court rules for bringing a claim depend on the legal jurisdiction where the claim is brought and whether the claim is a public law or private law claim. Challenges to the lawfulness of a government decision are normally made by way of judicial review in the UK. While a private law claim, involves a dispute that relates to individual concerns that arise between private parties, such as a claim for nuisance or misleading advertising. Two key differences between public law and private law claims are:


There is a strict time limit for bringing a judicial review –up to three months but can be just six weeks in a planning case. Once issued, the case generally moves at a faster pace than a private law claim, as it is important that an early decision is reached in the public interest. While a private law claimant usually has more time prepare the case before filing and sometimes the case can take years before a full trial.


In the UK the general rule is the loser pays the winner’s reasonable costs of the case. A difference between an environmental judicial review claim and a private law claim is that in the former the court can set a cap on what the claimant must pay if it loses the case known as an Aarhus costs cap. This provides the claimant with some certainty on the financial risk, but such costs caps are not available in private law claims.

  • What will the environmental litigation landscape look like in 2023?

One thing I know for certain is that litigation is here to stay – and ramp up. While governments and businesses continue to fail to meet their legal obligations for   environmental harm and its impacts on nature and people, affected claimants and those acting in the public interest like ClientEarth, will turn to the courts.

This could take a variety of forms, for example challenges to stop fossil fuel developments; compel public authorities to take more and faster action to comply with their legal obligations to reduce carbon emissions; protect human health by ensuring companies reduce and clean up their plastic pollution; and challenges to companies that greenwash – saying one thing and doing another.

  • How can lawyers be agents of change for a sustainable future?

The law is a set of rules by which society is governed and a lawyer’s job is about understanding what the relevant rules are and when necessary, enforcing those rules.

At ClientEarth, we work on the full cycle of the law – it’s not just about going to court, it’s about identifying what new laws are needed, helping write the right laws, ensuring that they are implemented and enforced effectively, and then, if we have no choice, taking steps to compel those responsible to comply with them.

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