On the eve of this week’s UN Climate Change Conference in Bali, two new reports show how tantalizingly able we are to reduce our climate footprint — and how frustratingly far we are from taking the needed steps to do so.

McKinsey & Co., the global management consultancy, last week released a report showing how the U.S. can reduce greenhouse gas emissions by one-third to one-half by 2030 “at manageable costs to the economy.” McKinsey analyzed more than 250 options, including efficiency gains, shifts to lower-carbon energy sources, and expanded carbon sinks.

The McKinsey study follows on the heels of other studies over the past year or so (see, for example, here, here, and here). All have similar conclusions: climate change can be addressed, in large part, with minimal hit to the global economy — but only if we act sooner than later.

Those two parts of the equation — profitable solutions resulting from immediate action — are simple enough, though they seem to elude many corporate chieftains and policymakers. McKinsey drives it home in no uncertain terms, stating that many of the opportunities available to us are “negative cost,” meaning they involve investments that pay for themselves over time. In fact, it says, the cost of not acting is significant:

For example, says McKinsey, the cost of building energy efficiency into an asset — a building, a car, a manufacturing process — when it is created “is typically a fraction of the cost of retrofitting it later, or retiring an asset before its useful life is over.”

McKinsey calls for a portfolio of “strong, coordinated policies” to capture greenhouse gas reductions efficiently across industry sectors and geographies, as well as accelerated development of “a low-carbon energy infrastructure” — everything from plug-in hybrid vehicles, to cellulosic biofuels, to carbon capture and sequestration — along with streamlined approval and permitting procedures to speed up energy infrastructure investments (including, alas, new nuclear power plants).

The McKinsey report was joined last week by a new report from the Confederation of British Industry, the U.K.’s counterpart to the U.S. Chamber of Commerce, which reached similar conclusions. “The next two or three years will be critical,” it begins. “A much greater sense of urgency is required if the U.K. is to meet its targets for reducing greenhouse gas emissions at an affordable cost, and to establish an international leadership role in the low carbon economy of the future.”

This, from a country that already seems well on its way to progress on the climate front, as I noted a few months ago. Yet despite a flurry of activity on climate in the U.K., the CBI concluded that it’s not enough.

Failure to act now will mean that the costs of tackling climate change in the future will be much higher. The U.K. will also miss out on the commercial opportunities that will emerge on the pathway to a low carbon economy.

The report calls for a shift to a world “where carbon becomes a new currency — so that consumers and businesses are rewarded for making the right choices. Carbon has to be priced according to supply and demand, under a system which leads to lower emissions, crosses national borders, and rewards good behaviour.”

This needn’t break the bank, says CBI. Its analysis of additional actions to be taken amount to an investment of around £100 a year per U.K. household (equivalent to about US$205 at today’s rates).

It all seems so rational. And yet . . .

For us Americans, it would be easy to shrug this off to the lack of leadership on climate issues from both the White House and Congress over the past — well, dozen years or so. And while leadership has been sorely lacking in this arena, there’s a critical role for business and consumers. The CBI report, in fact, identified consumers as “the essential driver for change.”

That last sentence is the key. For citizens to take the lead — as shoppers, voters, employees, or investors — we’ll need reliable and consistent information about the consequences of our choices, much wider access to energy-efficient products and services than is currently available, and incentives to encourage changes in well-ingrained habits.

That’s where the road to a low-carbon future involves a partnership between consumers and companies — and, ideally, their political leaders.