Seven in 10 people think banks and other savings providers should do more to show them where their money is being invested.
That's according to research from ethical lender Triodos Bank, which found 70 per cent of people would like to see more transparency from providers generally to show where their money is going.
Two-thirds (65 per cent) did not know whether their money or savings currently go towards supporting fuels that may have an environmental impact, such as oil, gas or coal.
Half (50 per cent) said they did not want their money to support fossil fuels, the survey of more than 2,000 people across the UK found.
Bevis Watts, chief executive of Triodos Bank, said: "The banks should be using the money saved or invested with them to protect the long-term interests of their customers in creating a sustainable future.
"They are making fossil fools out of customers, by using their savings to fund fossil fuel projects that are harming everyone’s future, and banks should be pressuring energy companies to change faster."
NGO BankTrack calculated that the top UK banks have poured approximately Sh20 trillion into financing fossil fuels since the Paris Agreement was adopted in 2016, including Sh5.8 trillion for the expansion of fossil fuels, of which Sh1.7trillion was invested in fracking.
And cutting off that funding is a key aim of many campaign groups - seeing Greanpeace launch protests against Barclays earlier this month.
Images of Barclays customers with slogans including "Stop Funding Fossil Fuels" were stuck on windows, tape places across doors and pop up exhibitions staffed by Greenpeace activists blocking access to branches in Belfast, Cardiff, Edinburgh, London and Manchester.
Greenpeace said it took action as bank backed polluters to the tune of £66.5billion between 2016 and 2018 - including support for coal and tar sands and fracking companies.
Morten Thaysen, Greenpeace UK climate finance campaigner, said: "Banks are just as responsible for the climate emergency as the fossil fuel companies they fund, yet they’ve escaped scrutiny for years."
A Barclays spokeswoman told Mirror Money: “We recognise that climate change is one of the greatest challenges facing the world today, and are determined to do all we can to support the transition to a low carbon economy, while also ensuring that global energy needs continue to be met."
Barclays told Mirror Money that it takes climate change "very seriously" - pointing out it already channels billions in funding to companies with environmental goals.
Its most recent reports show Barclays channelled Sh8.6trillion in social and environmental financing in 2019, and Sh3.5 trillion in 2018 including green bonds and renewable financing.
Perhaps the easiest way to take action is to switch.
Dr Alexandra Jellicoe, public and environmental health scientist, said: “The fossil fuels industry is by far the most damaging to our global climate. Reducing our dependence on these polluting fuels is arguably the single most urgent challenge we face if we are to avoid a really unmanageable climate crisis in the next few decades.
"We all need to make sure our money isn’t supporting an industry that is harming our planet. Switching your bank or savings provider is an effective way to make a difference and reduce the flow of money towards oil, gas and coal projects.”
Triodo's Watts felt more information and new products were key to this.
“There is a strong demand for much greater transparency over where banks invest their money, enabling customers to make informed choices," he said.
"The majority of people don’t want any of their money to support fossil fuels; so let’s give them the opportunity to act on this, and give them options for ISA savings and investments that combat the climate crisis, while also helping them put money aside for the future.”