IT is my great honor to write this preface for Professor Lester Brown's "Plan B, 4.0 - Mobilizing To Save Civilization." I would also like to take this opportunity to comment on green development in China.

Most of the Chinese people who know of Lester Brown, the famous American green thinker, learned of him mainly from two events.

First, in 1994-1995 he put forward the proposition of "who will feed China in the 21st century."

Second, since 2003 he began to publish the series starting with "Plan B: Rescuing a Planet Under Stress and a Civilization in Trouble."

The first question lead to the ongoing heated debates about China's food security.

The second series of works prompted some Chinese scholars, including me, to put forward the so-called Plan C for China's development.

Plan B

Plan B is an ambitious and policy-oriented green declaration by Brown about restructuring the world economic system. It is updated every two years, and four versions have been published from 2003 to 2009.

I appreciate the following major ideas from Plan B.

1. The traditional development model Plan A is characterized by carbon-intensive fossil fuel energy and linear economy, in other words, business as usual (BAU). This has already led to a dead end and cannot be sustained.

The direction for change is Plan B, a sustainable development plan characterized by low-carbon renewable energy and multi-cycling of materials.

The nature of Plan B is not anti-development, rather it replaces the pursuit of bigger growth with better development.

The key is to radically raise the productivity of the scarce natural resources.

2. The current global economy based on Plan A is already caught in a Ponzi scheme or trap, that is, economic growth is expanded excessively by drawing down the principal of the natural capital, rather than the interest.

Thus, once resources are depleted, Ponzi-type collapse follows.

This is because people's behavior is based on wrong assumptions about the relationship between economy and ecology.

The correct assumption is that the economic system is endogenous to the ecologic system, rather than the other way round as proposed by the mainstream neoclassical economists who stress unlimited economic growth.

3. The goal of Plan B is to guide the world from the old path of degradation and collapse, and on to a new path of reconstruction of ecological safety and the durable civilization.

Plan B consists of these four specific goals: cutting carbon dioxide emissions by 80 percent by 2020; stabilizing world population at 8 billion or less; eliminating poverty; recovering the earth's natural systems, including soil, water tables, forests, grasslands and fishing ground.

4. The transition from Plan A to Plan B should adopt the method of wartime mobilization to save the earth before the Ponzi bubble pops.

I agree with Brown's policy recommendations of sustainable development and ecological economy.

I think there's no question about rejecting Plan A (BAU), but whether we should apply Plan B absolutely in developed and developing countries needs further study.

Brown suggests in "Plan B, 4.0" that China should stop building coal-fired power plants altogether, right now, and shift to renewable energy, which, I am afraid, is not a viable idea.

This reminds me of the dramatic difference between his ideas with the one by Herman Daly, the famous American ecological economist cited many times by Brown in his book.

According to Daly, sustainable development or "degrowthed" development should first target the northern developed countries, while the key for the southern developing countries is towards smart growth or growth within natural limits.

That is because the basic needs of developed countries are already met, and they need to "lose weight" in terms of material consumption and eco-footprint.

Developing countries, by contrast, are like adolescents and their basic needs are not yet satisfied; thus, they need reasonable resources, environment consumption and expansion.

This means that the many ideas and policy recommendations in Plan B are definitely important and necessary for the green transformation in developed countries, but they need further processing to be applied in China for its green development.

On the one hand, China's green development should try to avoid the traditional Plan A path pointed out by Brown, and on the other hand, China needs to avoid the path of resource and environment protection without economic and social development.

Therefore, the biggest lesson we draw from Brown's book is that we need to have yet another Plan based on the principle of sustainable development - how we can develop China, a large developing country with a big population still in poverty, along a path of relative decoupling of resource and energy consumption with social and economic development.

Plan C

China's Alternative Development Plan would enhance social and economic development but leave a smaller carbon footprint than Western growth.

This way is what I call Plan C.

Otherwise, we simply cannot reasonably comply with the demand by some developed countries that China immediately and extensively curb its overall emissions of carbon dioxide or its per capita emission.

Even so, I emphasize the extreme importance and enlightment of Plan B for China's green development.

First, the ideas of sustainable development and ecological economy in Plan B are of generic significance and are very useful for thinking about China's alternative development.

Second, the major challenge confronting China now is still to avert the traditional way of Plan A.

The alarm raised by Brown is relevant for China in its green transformation.

Especially before our own Plan C was figured out, the criticism of Plan B from some Chinese experts and officials tends to lean towards Plan A.

Third, on the earth where natural resources are limited, it is ethically unfair and practically difficult if developed countries do not play an exemplary role in promoting Plan B.

(This article is based on Zhu Dajian's preface to a Chinese translation of the above book due out this month. Zhu is professor and director of the Institute of Governance for Sustainable Development, Tongji University.)