ClientEarth is an environmental law charity,[1] with offices in London, Brussels, Warsaw, Berlin, Beijing, Madrid and Los Angeles.

[9] ClientEarth is attempting to make it a legal right for European citizens and non-governmental organisations (NGOs) to bring environmental cases to court.

[12] In July 2011, ClientEarth submitted a case to the High Court of Justice of England and Wales, challenging Defra on its failure to protect British citizens' health from the harmful impacts of air pollution.

[14] In total ClientEarth has won three High Court rulings ordering the British government to produce stronger plans to improve air quality.

[19] Following their legal action, the EU's top court has issued multiple €10,000 fines to the Bavarian government for failing to act on the ruling.

[20] In 2017, ClientEarth launched legal action against Lombardy, Europe's most polluted region to force the authorities to tackle the public health emergency.

[22] In September of the same year, the four groups filed a second lawsuit against the commission, to attempt to gain the release of documentation regarding the negative environmental impact of biofuels.

Following a complaint by ClientEarth's environmental lawyers and a multi-year legal battle, Poland's Supreme Administrative Court ruled that the Północ coal plant will never be built.

[26] Ostrołęka C, Poland [27] In October 2018, ClientEarth filed a challenge against Enea over financial risks to investors amid rising carbon prices, cheaper renewables and EU reforms on state subsidies for coal power plants.

The approved plan gives preferential access to the wholesale electricity market in Spain for power plants that run on domestic coal.

Spanish electricity utilities, including Gas Natural, Iberdrola and Endesa have claimed that this will force them to withdraw from contracts for cheaper imported coal and buy more expensive, lower-quality domestic coal, while the parties have also argued that the decision breaches European laws on state aid and the environment, and that the Spanish government aid will unfairly skew the European energy market.

In February 2020 their CEO James Thornton wrote a letter to Barclays' chairman warning of the risks associated with continuing to invest in fossil fuels.

[35] ClientEarth also provided support to the Church Commissioners for England's call for commodities giant Glencore to significantly strengthen its commitment to combat climate change.

[37] In August 2018 ClientEarth reported three large British insurance companies – Lancashire, Admiral and Phoenix – to the Financial Conduct Authority for failing to explain the risks from climate change.

[5] An investigation by ClientEarth in 2010 found that 32 of 100 fish product labels at nine supermarkets had unverified or misleading claims on sustainability or protection of the marine environment, such as "dolphin-friendly".

In addition, the organisation expressed concern that labels often did not make clear that many fish products came from threatened stocks, or that they were caught using techniques that had potential to damage the environment or other species.

They argued that the company used a highly unrealistic scenario when predicting future energy demand, enabling them to justify continued investment in risky extraction methods.

[49] In early‑2022, ClientEarth began civil proceedings against the 13 directors of the UK‑based Shell plc oil major in an attempt to hold these individuals personally responsible for failing to adequately prepare the company for a transition to carbon neutrality.

ClientEarth lawyer Paul Benson remarked that "it's the first time that anyone has sought to hold the board accountable for failing to properly prepare for the net zero transition".

In June 2019, Pink Floyd band member David Gilmour pledged to donate US$21.5 million, raised from the sale of his guitar collection.