Taking the World Lawyers’ Climate Pledge to the UK Supreme Court

Tim Crosland, Director, Plan B.Earth. On 18th October, Tim Crosland’s appeal will be heard before the UK Supreme Court, concerning his conviction for contempt of Court. Tim Crosland explains why he is relying on the Pledge in his appeal.

In June 2018, the UK Government already knew.

It knew that expanding Heathrow Airport would result in the carbon dioxide emissions just from UK aviation rising to around 40,000,000 tonnes per year by 2050.

It knew that global carbon emissions would need to decline to net-zero by 2050 for there to be any meaningful chance of limiting warming to 1.5˚C.

And it knew also that the consequences of breaching1.5˚C would be dire – for humanity and all other life.

But in June 2018, the UK Government disregarded those facts and approved plans for a third runway at Heathrow. In announcing a decision that would have vast implications for the UK’s carbon budget for decades to come, the Government told the public only this:

The Government’s position remains that action to address aviation emissions is best taken at the international level, given aviation is an inherently global industry and climate change is a global rather than local environmental issue … [our] analysis found that under both scenarios all schemes were consistent with the UK’s carbon obligations

Government response to the consultations on the Airports National Policy Statement, p.75ff.

So how did the UK Government reconcile the projected emissions arising from Heathrow expansion with the requirements for 1.5˚C? It turns out they didn’t.

The first case: challenging the airport decision

In the years that followed the third runway decision, civil society groups—and among them PlanB.Earth—challenged the legality of the Government’s decision in the UK courts, a process known under the law of England and Wales as judicial review. In the course of those proceedings, both sides are obliged to disclose material evidence, and those disclosures threw up one startling revelation.  For reasons which have never been explained, the Government had assessed the expansion plans not against the Paris Agreement temperature goal, but against the historical and discredited 2˚C goal, which had been rejected by the international community in December 2015 as exposing humanity to intolerable risk.

The Judges of the UK Supreme Court will be required to read the Pledge, to consider it, and to reflect on their own role—and the role of the law—in this, a time of global environmental crisis

When Plan B’s case came before the Court of Appeal, the Court ruled that the Government should have used the Paris Agreement temperature limit as its benchmark (not the 2˚C limit). The Government’s failure to consider the Paris Agreement, and in particular its 1.5°C threshold, tainted the process:

It is common ground that the Secretary of State did not take the Paris Agreement into account in the course of making his decision to designate the ANPS … In particular, in our view, it was a basic defect in the decision-making process that the Secretary of State expressly decided not to take into account the Paris Agreement at all. That was a fundamentally wrong turn in the whole process.

Plan B.Earth v Secretary of State for Transport, [2020] EWCA Civ 214, [186] and [276

Tellingly, the UK Government did not appeal the ruling. But Heathrow Airport Limited, the commercial company behind the £14bn project, took it to the Supreme Court.

Contempt of the Supreme Court

I represented PlanB.Earth in the proceedings before the Supreme Court. The case had proceeded through all of its usual stages – the filing of both sides’ written submissions, the oral hearing before the Justices of the Court, and the Court’s deliberations had been going on for some time. It was on the 9th December 2020 that I received the draft judgment of the Supreme Court under embargo. The purpose of draft judgments is to identify any factual errors prior to publication. Normally that might be a matter of correcting a few dates, perhaps a misspelt name or two.  But this time, there were some absolute clangers. The Supreme Court reversed the judgment of the Court of Appeal, and did so on the basis of three huge errors of fact:

  1. it omitted to mention the Government’s reliance on the discredited 2˚C target;
  2. it omitted to mention the inconsistency between the Government’s own estimate of the carbon emissions resulting from Heathrow’s expansion and the 1.5˚C Paris goal; and
  3. it stated that, contrary to the Government’s own admission, the Government had taken the Paris Agreement into account.

I wrote to the Court to draw attention to these errors and said that if a judgment were published that suppressed from the public the extreme danger of Heathrow expansion, which had been in evidence before the court, I would have no option but to make a public statement.

On the 15th December, the day before the judgment was due to be published, I broke the Court embargo to highlight the true position, which the final Supreme Court judgment continued to conceal from view. That the expansion of Heathrow would lead to a huge increase in aviation emissions; that those emissions would seriously hamper the UK in its decarbonisation efforts; and that the go-ahead had been given on the basis of a flawed process, taking into account only an outdated target that was at odds with the UK’s international commitments. I knew that there would be serious consequences to my actions, and I was not disappointed: I was charged with contempt of court and on the 10th of May, the Supreme Court found me guilty. I was lucky to escape prison (the traditional outcome for contempt), but I was fined £5,000 and ordered to pay costs of £15,000.  But I felt that I must speak up.

The Time To Act is Now

On the 18th of October 2021, my appeal will be heard before a differently constituted panel of the Supreme Court (an interesting point for the constitutional lawyers since this has never happened before). I am arguing that the process before the Supreme Court panel was tainted by factual errors and that it breached the UK Human Rights Act, in particular Article 10, the right to freedom of expression.   When I broke the embargo in December 2020, I had not signed the World Lawyers’ Pledge on Climate Action, because it had not yet been written, but I signed it eagerly when it was published this Autumn. Since the pledge captures the principles that led me to breach the embargo, I refer to it in my Grounds of Appeal. The Judges of the UK Supreme Court will be required to read the Pledge, to consider it, and perhaps to reflect on their own role—and the role of the law—in this, a time of global environmental crisis.

Further, the action I took was consistent with the World Lawyers’ Pledge on Climate Action I have since signed, initiated by researchers at the Max Planck Institute for Comparative Public Law and International Law ….

…The science of climate change is clear—we are facing a climate emergency. Climate change is part of an unprecedented series of overlapping and mutually reinforcing ecological crises, and time is running out to prevent its most dangerous impacts on the environment and on human and other life. The 2015 Paris Agreement calls on States to hold ‘the increase in the global average temperature to well below 2°C above pre-industrial levels’ and to pursue ‘efforts to limit the temperature increase to 1.5°C above pre-industrial levels’. This requires immediate and systemic changes, societal transformations, and concerted action to drastically reduce greenhouse gas emissions within this decade, and to reach global net-zero emissions of CO2 around 2050…”

Tim Crosland’s Grounds of Appeal, citing the World Lawyers’ Pledge on Climate Action.

The Pledge provides a basis for the legal community to exercise collective power and influence in attempting to avert the ultimate crime against humanity and life on earth. I am pleased to be able to rely on it in court.


Tim Crosland is Director of the charity Plan B.Earth, which advances strategic legal action to tackle climate change. Plan B and 3 UK citizens are currently suing the UK Government for violations of the right to life, the right to family life and the prohibition on discrimination in the enjoyment of those rights (ECHR Article 2, 8 & 14) arising out of its continued support for the global carbon economy.  He has previously worked as a barrister in private practice and also as a lawyer for various governmental organisations including the National Crime Agency.

Tim’s appeal will be live-streamed from the UK Supreme Court on 18 October here.

See also:

“Lawyers line up to support Supreme Court contempt barrister”, Law Society Gazette

Letter to the UK Supreme Court from leading lawyers, climate scientists and economists

Tim Crosland explains why he disclosed the Heathrow judgement (BBC)