Earlier this year, Rhian-Mari Thomas, head of the Green Finance Institute (GFI), found herself in the snowy peaks of Davos, ready to make an important pitch to Rachel Reeves, the UK’s future chancellor. The GFI, a government-supported organization that promotes environmentally friendly financial products in the UK, had been keeping a close eye on Labour’s £28 billion green investment pledge. Thomas, however, believed this amount was too much to take from taxpayers. She felt the private sector could contribute significantly to these green projects, which was a crucial point she wanted to convey to Reeves.

Thomas’s frustration with Labour’s approach was evident. She believed that involving private investors who were eager to fund green projects would be a more effective strategy. “I was frustrated,” she recalls, “and I told her exactly that.” She argued that the GFI could guide Labour’s national wealth fund, making sure it was more affordable for taxpayers.

Soon after, Labour’s green investment pledge was cut in half, with Thomas taking on a leadership role in shaping the new plan. She became the chair of Labour’s national wealth fund taskforce, working alongside influential figures such as former Bank of England governor Mark Carney and top executives from Aviva, NatWest, and Barclays. This collaboration led to the creation of a £7.3 billion fund, launched just days after Labour’s landslide victory in July.

For Thomas, this was a major career milestone and a validation of her decision to leave the banking world in 2018 for a role that aligned more closely with her environmental values.

Growing up in Cardiff in the 1970s, Thomas was deeply influenced by her parents’ commitment to reducing their carbon footprint. Her family made conscious choices like avoiding red meat due to concerns about cattle farming in the Amazon and choosing public transportation over driving. Her father’s dedication to these principles was so strong that neighbors often wondered if he had lost his driving license. This upbringing laid the foundation for Thomas’s lifelong commitment to environmental causes.

As a teenager, Thomas spearheaded environmental initiatives at her high school on Barry Island. She started a paper recycling program and led a campaign against harmful chemicals in hairsprays. This passion for sustainability continued as she pursued higher education, studying physics at the University of Bath and later earning a PhD at Trinity College Dublin.

After completing her studies, Thomas was recruited by Barclays’s investment bank, despite having little knowledge of the financial industry. She recalls being unaware of the differences between an investment bank and a post office. Nevertheless, Barclays Capital, led by Bob Diamond at the time, was eager to hire graduates with advanced degrees, offering a significant financial incentive to those who performed well on their psychometric tests. Thomas described the £4,000 offer as a fortune at the time.

Thomas quickly adapted to her new role, working on leveraged finance and private equity deals. However, after the 2008 financial crisis, she transitioned to retail and corporate banking, eventually becoming the chief commercial officer at Barclaycard, Barclays’s credit card division.

By 2016, Thomas began to feel unfulfilled in her career. The signing of the Paris Agreement the previous year had reignited her passion for environmental issues. She questioned whether her skills and experience were being used in the best way possible. Thomas recognized that sustainability needed to be more integrated into business practices and that the financial sector would only change if there were clear economic benefits.

In 2017, Thomas launched a green banking council within Barclays, which was instrumental in developing the first green mortgage product. This product offered customers discounts on properties that were more environmentally friendly. Her efforts eventually led to her being named Barclays’s first head of green banking.

By the time the UK government and the City of London Corporation launched the GFI in 2018, Thomas knew her next move. She was ready to take on a new challenge, leading the charge in promoting green finance and helping shape a more sustainable future for the UK.

Her journey from frustration at Labour’s original green investment pledge to leading a task force that reshaped it into a more balanced and sustainable plan is a testament to her determination and vision. Rhian-Mari Thomas has proven that with the right approach, the private sector can play a significant role in addressing environmental challenges while ensuring that taxpayer money is used wisely.