LONDON -- Politicians, scientists, businesspeople, academics, economists and environmental groups are among a loose coalition forming to push for a radically new measure of the costs of economic growth as a tool to help estimate the looming risks posed by climate change.

Instead of using the universal yardstick of gross domestic product, which looks only at production and consumption, to gauge economic well-being, the unusual amalgam wants a far broader measure -- or rather range of measures -- that takes account of sustainability, environmental damage, biodiversity and social impacts.

Lord Nicholas Stern. Photo courtesy of Wikipedia.

The new measure, which some call GWB for Global Well-Being, will be among the larger issues raised at the so-called Rio+20 international talks in Rio de Janeiro beginning June 13. The U.N. Conference on Sustainable Development will mark the 20th anniversary of talks that led to the Kyoto Protocol to curb climate change.

The debate over GDP starts with the assertion that what college students learn about it in Economics 101 may overstate the real value of continued economic growth.

"GDP absolutely shouldn't be the sole measure. It is absolutely clear that we need to go beyond GDP. It is a very narrow measure of economic welfare," Lord Nicholas Stern, head of the influential Grantham Research Institute on Climate Change and the Environment at the London School of Economics, told ClimateWire. He is also the author of the seminal 2006 Stern Review on the economic impacts of climate change.

"In fact, the time to move beyond it is already past, and we are already doing that," he added on the sidelines of a series of public lectures on climate change that he was giving at the university.

'Just stopping growth doesn't deliver'

"Basically, we have to break the relationship between production and consumption on the one hand and emissions on the other," he told a packed lecture hall. "Just stopping growth doesn't deliver. Unless we break that relationship, we are in very big trouble. We are going to have to think about changing patterns of consumption and changing patterns of production."

He said the world is emitting about 50 billion metric tons a year of carbon dioxide, a figure he said needs to be slashed to less than 20 billion in less than 40 years if atmospheric concentrations of the gas -- already around 392 parts per million -- are to be kept below the 450 ppm at which scientists say catastrophic climate change will kick in.

Although Stern did not explicitly make the link in his lectures, the inescapable fact is that around the world, governments still focus on GDP to report their success or failure in an economic system that has relentless growth in production and consumption as the overriding goal.

Stern, a former chief economist at the World Bank and former head of the U.K. government's economic service, is not the first respected economist to point out the failure of GDP as a measure of success.

U.S. economist and Nobel Prize laureate Joseph Stiglitz has been making the point for years, most recently in the book "Mismeasuring Our Lives: Why GDP Doesn't Add Up," which was in effect the distillation of the 2009 final report of the international Commission on the Measurement of Economic Performance and Social Progress he chaired for French President Nicolas Sarkozy.

"It has long been clear that GDP is an inadequate metric to gauge well-being over time, particularly in its economic, environmental and social dimensions, some aspects of which are often referred to as sustainability," the report says in its conclusions.

Push runs stronger in Europe

Over the years, others have also pointed to the failure of the accepted economic model to take account of the true costs of growth.

The European Commission at the start of 2008 set up the Beyond GDP initiative to explore alternatives to GDP, and British Prime Minister David Cameron last year gave the go-ahead for a new GWB index, the first example of which is expected in the middle of this year.

Former U.S. Vice President Al Gore, who is currently chairman of an investment fund, has also waded into the issue. He has described high-carbon fuels as potentially stranded assets when they are made to carry the full costs they impose. Gore has likened them to the subprime mortgage crisis that triggered the 2008 global economic meltdown. So far, the Obama administration has said little about its objectives in the Rio talks.

An outspoken group of nongovernmental organizations has banded together to form the Green Economic Coalition. Their campaign, called "Measure What Matters," is pushing for a radical revamp of the accepted economics.

At a recent meeting, one participant noted with some satisfaction that the first draft of the declaration to be discussed at Rio+20 "makes note of the limitations of GDP as a measure of well-being."

What your economics professor didn't tell you

Ross Jackson, a Danish businessman, philanthropist and author, makes the same point in his new book due out later this month, "Occupy World Street: A Global Roadmap for Radical Economic and Political Reform." He argues that one of the problems is that GDP is a blanket measure with severe limitations that is widely used yet poorly understood.

"GDP is not an appropriate measure for the effectiveness of economic policy. What we really need for that purpose is a measure of well-being, i.e., the net human results of all the economic activity. This point of view is slowly gaining converts in academic circles, but GDP is still heavily entrenched among mainstream economists," he asserts.

A group of 20 winners of the Blue Planet prize -- founded at the 1992 Rio Earth Summit for outstanding contributions to the understanding of global environmental problems -- added their voices last month to the call for the replacement of GDP as a measure of wealth.

Signatories to the 21-page document include Stern; former Norwegian Prime Minister Gro Harlem Brundtland, whose 1987 report, "Our Common Future," sowed the seeds of the first Rio Earth Summit; NASA's James Hansen; former U.K. government chief scientist Robert May; and James Lovelock, who formulated the Gaia hypothesis of the Earth as a living organism.

"Unsustainable growth is promoted by environmentally-damaging subsidies in areas such as energy, transportation and agriculture and should be eliminated; external environmental and social costs should be internalised; and the market and non-market values of ecosystem goods and services should be taken into account in decision-making," says the report, which was presented to government ministers from around the world at a U.N. meeting in Nairobi, Kenya.

"The time to act is now, given the inertia in the socio-economic system and that the adverse effects of climate change and loss of biodiversity cannot be reversed for centuries or are irreversible. Failure to act will impoverish current and future generations," it concluded.