The most accurate advance comment on Common Wealth described it as a 'field manual, a guide book'. That is an apt description. There is nothing ground-breaking here, Jeffrey Sachs avoiding the bombastic, jargon-laden prose favoured by many academics. Sachs, along with Paul Krugman, is among the most readable economists in print.

In clear, forcefully argued sentences he makes interesting yet hardly revolutionary points. In the past 200 years technological advances have far outstripped social advances. Technology has also increased society's impact, generally unfavourably, on the environment, often because of exploitation of resources by the private sector.

On the other hand, allowing common use of resources does not necessarily lead to better stewardship. 'An example of the global commons is the ocean floor beyond national borders, where fishing fleets are free to destroy natural ecosystems as they drag their trawls on the ocean bottom,' he writes.

He nails his colours to the mast when he defends countries with relatively high levels of government intervention. He says social-welfare states have higher living standards and lower poverty rates than those with so-called free-market economies.

In a free and unregulated market, for example, he argues power plants have no incentive to pay for scrubbers to cleanse their emissions, regardless of the environmental and social benefits. 'A public policy to correct the market prices is needed to give the power plants the incentive to buy the smokestack scrubbers,' he writes.

His writing on sustainability is intriguing. For example, his account of the arrival of hunter-gatherers in the Americas at the end of the most recent ice age, about 13,000 years ago, illustrates the need for conservation. The hunter-gatherers found a continent full of large land mammals, including horses, which they hunted to extinction. 'Horses, had they not been driven to extinction, would have provided the indigenous Americans with motive power for ploughs, transport, water wells and the like, but they were gone before these technological possibilities were recognised.'

When horses did return to the Americas they were brought by the conquering Spanish.

Sachs' comments on China may raise eyebrows. While he concedes that it is 'unfair in a way to single out China for following in the well-trodden path of the rich countries, being no more or less guilty of their environmental harm ... the scale and rapidity of China's economic ascent make the country's global environmental impact especially vivid. China is already causing massive global change and much more is to come.'

How is that so? China is bringing on stream the equivalent of two 500-megawatt coal-fired plants a week, equivalent to the total capacity of Britain's power grid. Its appetite for raw materials, for example soya beans, will increase deforestation in the Amazon to make way for farmland. Its oil imports will push up energy prices and increase the use of biofuels, while its demand for exotic animal products could bring about the extinction of several large mammals in Africa and Asia.

Sachs writes fluently on non-economic matters such as water usage, population growth and poverty in sub-Saharan Africa and the environment. His explanations of climate change and its implications are lucid and convincing. He argues persuasively that rich countries can do much to minimise environmental degradation through greater use of energy-efficient devices and carbon storage and by cleaning up industry.

So what does Sachs recommend? He believes rich countries should give more in the form of direct foreign aid. He argues the economic cost - as a percentage of gross domestic product - of reducing energy use and shrinking our carbon emissions is low compared to the cost of ignoring the problem.

He saves a broadside for the government of George W. Bush for its stance on climate change and the environment - none of which is new but which makes good reading.

Reading anything by an economist of Sachs' status is worth the time and effort, but those looking for something new from the man the New York Times Magazine called 'the most important economist in the world' will be disappointed.