For anyone who maintains that climate change is not going to affect our lives, it may be worth listening to the concerns of America's publicly traded corporations.

These companies, which tend to be of a more conservative persuasion and not given to hyperbole, are increasingly concerned about how climate change is likely to damage their operations.

A study into disclosures on behalf of 767 institutional investors with $92tn in assets S&P 500 companies – released today by sustainable-economy non-profit CDP – shows not only that the physical risks from climate change are increasing in urgency, in their assessment, but also that the impacts are already hitting the bottom line.

Companies are quickly recognising how their business models are likely to be affected by climate challenges ranging from extreme weather events to a shortage of key resources, the study finds.

In 2011, a quarter of S&P 500 companies were worried that climate risks were either already upon them or were expected to hit within the next one to five years. Just two years later, the figure has jumped to just under half.

A similar pattern has emerged when it comes to the companies' estimate of the likelihood of these risks becoming reality. In 2013, half the companies characterized their perception as ranging from "more likely than not" to "virtually certain", up from just over a third of respondents in 2011.

The research, based on an annual survey of 767 institutional investors with $92tn in assets, comes after Walmart's UK supermarket chain Asda told Guardian Sustainable Business that 95% of its global fresh produce range is already at risk from global warming.

Many US companies say they are already seeing significant impacts to their business operations, ranging from damage to facilities, reduced product demand, lost productivity and write-offs.

"Dealing with climate change is now a cost of doing business" says Tom Carnac, president of CDP in North America. "Making investments in climate-change-related resilience planning both in their own operations and in the supply chain has become crucial for all corporations to manage this increasing risk".

The corporate cost of extreme weather

There are many examples within the CDP report of how extreme weather has already disrupted businesses over the past three years.

A drought in China means clothing giant Gap faces a spike in cotton prices, while closer to home, Union Pacific was hit with an 11% decline in freight revenue from corn shipments as a result of a lack of rainfall.

Wildfires in San Diego cost Sempra Energy more than the $1.1bn it held in liability insurance coverage, and HP saw revenues fall 7% following the 2011 floods in Thailand. Meanwhile, Superstorm Sandy cost Consolidated Edison $431m.

Other recent studies have also noted growing climate change risks. Research released earlier this year from Schneider Electric – which concludes that climate change is directly related to an increase in extreme weather events – projects it will raise business risks such as higher food and commodities costs, increased financial risks, supply chain disruptions, potential transportation disruptions and new threats to crops from new insects.

Meanwhile, a 2013 article in the Journal of Flood Risk Management estimated that flooding – which costs the US more than $7bn in damages annually, according to the US Geological Survey – estimated those damages would grow approximately 30% by the end of the century.

Virtually every part of the business is at risk

In the CDP report, drinks giant Dr Pepper Snapple Group highlights how unusual weather or long-term climate changes may affect virtually every part of its business, ranging from higher prices and a lack of availability affecting its raw materials, energy and fuel, to lower demand for its products.

Its concerns particularly focus on water, which is the main ingredient in virtually all its products. "Climate change may cause water scarcity and a deterioration of water quality in areas where we maintain operations," it says.

"The competition for water among domestic, agricultural and manufacturing users is increasing in the countries where we operate, and as water becomes scarcer or the quality of the water deteriorates, we may incur increased production costs or face manufacturing constraints which could negatively affect our business and financial performance. A portion of our cost of sales, or $2.5bn, could be at risk through increased costs to our supply chain as a result of these risks."

While US companies talk of dangers ahead, what is worrying is how few of them are taking significant action to reduce their emissions.

A business 'imperative'

This was highlighted recently by a report from Ceres, a non-profit focused on sustainable business, based on an analysis of 613 publicly listed US companies representing three-quarters of the country's total stock-market capitalization.

It showed that two-thirds of the companies have failed to establish time-bound reduction targets for greenhouse gas emissions and 94% have not set quantitative targets to increase renewable energy sourcing.

"US companies are simply not taking the comprehensive actions necessary – through energy efficiency, renewable energy procurement and other steps – to tackle climate change," according to the Ceres report. "It is imperative that many more companies shift from being reactive to proactive in embracing the sustainability challenges that lie ahead. The need for investors, businesses, NGOs and other stakeholders to fully engage in the essential work of creating a sustainable economy has never been more urgent."