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When it comes to the impact that a changing global climate will have on both natural and human environments, China is a place to watch. Roughly one out of every five people on Earth lives there, and those 1.3 billion people are actively seeking xiaokang, or a "well-off" life. China's rapid economic growth, says Ding Yihui, a professor at the National Climate Center in Beijing, has worrisome implications not just for climate but for biodiversity, ecosystems, human health, and air quality, both within China and beyond its borders. But, Ding argues in this interview, it's not too late to take action to minimize the potentially disastrous effects of high consumption—not just in China but in the United States and other countries that have or covet xiaokang.

The debate

NOVA: Is global climate change real? Is the human race altering the climate?

Ding: There is no question about the fact of climate change. From the readings of global temperature over the past 140 years, the temperature has increased by 0.4 to 0.8°C. Another fact without question is that greenhouse-gas emissions are on the rise. Over the past 200 years, greenhouse-gas emissions have increased by about 268 to 372 parts per million this year.

The question remains on the causes of climate change. Some believe it is caused by human activity. Their research is mostly based on model simulation. Yet some scientists think it's probably too early to draw the conclusion that it is caused by human activity. They believe natural forces such as radiation from the sun might be more important. The question is not whether the globe has become warmer; that is a fact. The question is how to explain it.

NOVA: Why is there a debate over the cause or causes of global warming?

Ding: The reason is we don't have very good methods to test for natural and human causes, to separate the two. The only way is through climate simulation, in which we can put in human and natural factors then examine whether the simulation result is close to reality. But many scientists have doubts about that method. They have suspicions about the simulation's accuracy and the physics involved. Therefore, the only tool we have available to examine the causes of natural changes and human activity is left in doubt. We have to develop a better method.

Another reason is our inadequate research and disagreement on historic data, because there were no measurements 140 years ago. All we have are substitute data, such as those from corals, ice cores, and tree rings. All these data are very sketchy, because they were collected from a single spot, which can't well represent a wider area—say, climate change in the Northern Hemisphere.

Impact in China

NOVA: Can you see signs of climate change in China?

Ding: You can see many signs of climate change here. The most obvious one is the decline in glaciers and snow precipitation in the west of China. Chinese scientists have found that the number of glaciers in this region have decreased by about 25 percent in the past 100 to 200 years. You find the snowline on mountain ranges such as the Kunlun and Tian Shan or even on mountains in the west of Yunnan Province in the south has obviously risen, and snow is melting. Collapsing and receding of glaciers are very common, too. This massive melting of glaciers has induced many natural disasters, including those spawned by glacier lakes. When a glacier melts, its ice water can accumulate at the bottom of a mountain valley, forming a lake. When the valley can no longer hold the water, the water can burst out and cause landslides.

“Given China’s economic condition, it will be impossible to cut down the use of coal as a major energy source in the next 20 years.”

Our biodiversity is in decline, too. Among the 11 types of major trees in China that we have surveyed, eight or nine are dwindling in their planting areas. The coniferous forests in China's northeast have decreased to a very small area, for example. Other trees such as pines and firs are dwindling in their areas as well, and there are very few tropical forests left in China now. They can only be found in small parts of Xishuangbanna in Yunnan Province and in the south of Guangdong Province.

China's rising sea level is also very serious, especially in such areas as the Bo Hai [Gulf of Chihli], the Changjiang [Yangtze] River Delta and the Zhujiang [Pearl] River Delta. The speed of rising sea level in China is consistent with the global trend [observed since the 19th century], an increase of 10 to 20 centimeters.

Human health has been affected, too. Because of global warming, for example, the number of people suffering from dengue fever has increased. Warm weather also causes discomfort for people, and the death rate is increasing. Things like that are all caused by climate change, about which we are all very concerned.

NOVA: How do you factor China's population into the global warming problem?

Ding: The growth rate of China's population continues to decrease, while China's emission of carbon dioxide keeps rising. The reason is quite simple. By the end of 2020, according to the development plan formulated by the Chinese government, China will reach the level of xiaokang, which means our life will be relatively comfortable, with our annual per-capita income reaching U.S. $1,000 or more.

China faces two problems. One is how to achieve the state of relatively comfortable life for every Chinese person. We must develop the national economy, increase productivity, and improve people's living standard. One major sustaining force in doing this is the use of large amounts of energy. The most important energy source in China is coal, which comprises 70 percent of total energy consumption in our country and emits large amounts of carbon dioxide and other air pollutants.

Given China's economic condition, it will be impossible to cut down the use of coal as a major energy source in the next 20 years. As we all know, it's impossible for China to develop large-scale nuclear power plants because of the concerns of safety and funding. China mostly uses hydraulic power plants, which will not comprise a very large portion of the country's energy supply in the future.

So in the next 20 years, China will continue to burn coal as a major source of energy. According to estimates by Chinese scientists, by 2020 China's consumption of coal will decrease by only a few percentage points, which brings the total amount down only from 70 percent to 60-something percent. As you can see, this is still a significant figure that guarantees a large amount of carbon dioxide emissions.

Despite the slowdown of China's population growth rate, I think coal mining and consumption will increase because of our economic development, so the total amount of emission will not decrease. We estimate that between 2020 and 2030, China's carbon dioxide emissions will probably increase greatly. (By then it will be hard to tell whether the U.S. or China is in first place!) Nevertheless, the Chinese government will try hard to decrease the emission rate and speed in the future. That's our goal.

NOVA: How significant is the burgeoning automobile market in all of this?

Ding: I think this question is very important, because private ownership of cars in China is becoming more common. Last year, 250,000 cars were added to Beijing, bringing the total number of cars in the city to about two million. The total population in Beijing, including the suburbs, is about 10 million. So there is a private car for every five people.

“These are the dual tasks that we are facing now: striving for development and protecting the environment at the same time.”

We scientists are very concerned about it. Firstly, more cars mean more emissions, among which carbon dioxide is a major one. Another important problem is that cars also discharge carbon monoxide [CO] and chlorofluorocarbons [CFCs], both of which cause ozone, another type of greenhouse gas that is harmful to human health, ecosystems, and plant and animal life. Cars also release fine particles into the air that limit visibility in the city and pollute the urban air.

As you know, China is going to host the 2008 Olympic Games. The Chinese government has promised clean air during the Olympics. In the next four years before the Olympics, the Chinese national and Beijing municipal governments will work hard to reduce the fine particles to a level allowed by the Olympics. It's an arduous task. Another important task is that we need to have tighter emissions controls, which as I understand it, will be the same as the European standard. The standard will help us to limit cars' emissions of fine particles, CFCs, etc.

NOVA: Given China's size, can it reach its development goals without causing climatic disaster?

Ding: I think the Chinese government should find ways to conserve the climate during the country's development, and adopt all means possible to reduce emissions. These are the dual tasks that we are facing now: striving for development and protecting the environment at the same time. It's very hard. But this is what I'm spending my time doing now: working to better predict the future and provide information for both the energy branches and the legislature in order to come up with policies to reduce emissions and improve energy efficiency so as to minimize the scale of disasters.

Acting globally

NOVA: Some people would say, "Okay, so the climate changed. So what? We'll be fine." Why should people care about this? What could happen?

Ding: Climate change has always been here, of course, and in the past the degree of change has been even larger than that of today. Then why are we so concerned about climate change now? The reason is very simple. Most climate changes in the past had natural causes, while climate change today is caused by the greenhouse effect induced by us humans.

Once the climate is changed, according to scientists' predictions, it is irreversible to a large degree. In the past, often a change has been sudden, say a jump of temperature by 10°C to 20°C. If that happens, we humans won't be able to adjust to it, and the living environment for the human race will be gone. We have discharged too much carbon dioxide, we have cut down too many forests, we have done too many things that we shouldn't have done, and we have damaged the climate.

I think we should look at climate effects not just for a few dozen years but for the upcoming hundreds of years. Even if we improve emissions now, the climate will continue to deteriorate because of climatic inertia. According to current predictions, even if we were to reduce or stop emissions now, the climate will continue to change for the next few dozen or even 100 years. The consequences are very serious.

NOVA: Is it too late to do something about this?

Ding: It's not too late for us to start doing this task. According to scientists, the real speeded-up change will take place in the next 100 years. Now, here at the beginning of the 21st century, we are armed with the United Nations Framework Convention on Climate Change, together with the Kyoto Protocol. If we start to reduce emissions now, we will probably be able to see effects between 2030 and 2050. Even with the few dozens of years due to the inertia of climate change, two or three generations after ours will enjoy the result of our effort. So I think with global cooperation, it's not too late. It's still relatively early.

For example, there was a Montreal Protocol on Ozone Depletion in 1982. Twenty years later, people were starting to see the effect of that protocol. The level of ozone [loss] is dropping. Many scientists are very happy about it. Thanks to the Montreal Protocol, peoples' efforts are being rewarded. I think it's the same with the problem of climate change: after 20 years, we'll most probably be able to see the slowdown of global warming. By that time, we'll feel our effort has not been wasted.

NOVA: Do you think the planet can support nine billion people living the lifestyle that the Chinese people aspire to now? How about within China itself?

Ding: This is an important question. How big will Earth's population be? Though we can't give an accurate calculation, nine billion is a very possible figure. We have six billion people now, and we very likely may add another three billion in 50 years. Some scientists estimate 12 billion total, which is an even more terrible prospect.

We are faced with three major problems. First is the security of grains. Our food is dependent on our grain supply. Can we provide enough grain to feed our population 50 years from now, especially under a worsened climate? The second problem is the water supply. The third has to do with diseases and human health. Will there be more suddenly erupted diseases such as the unexpected SARS we had this year? Scientists around the world are starting to pay attention to these three major problems arising from population growth.

“The developing countries can’t follow in the footsteps of advanced countries that have had high emissions and high consumption.”

For China, climate change will affect its grain yield, which according to Chinese scientists' estimates, will drop by 5 to 10 percent in the next decade due to more droughts, more plant diseases and insect pests, and different plant structure. However, scientists also estimate that the security of grain is not too much of a problem for China in the next 30 years. I think in the next 20 years, it's not too much of a problem for every Chinese to lead a comfortable life, as I just talked about—say, having 400 kilograms of grain secured per capita each year. (That 400 kilograms includes fodder for livestock.) However, it will be hard to tell what it will be like 50 years from now if the climate keeps deteriorating. The grain yield will drop further. Grain yield is dropping widely across the world, especially among developing countries, due to climate change.

There is also the problem of water. China's water supply is far less than that of many other countries. The north and northwest, some regions in the east, and some areas along the Yellow River and Huai River are suffering from water shortage. The north of China has suffered from droughts for years. The Chinese government has come up with a plan of allocating the water from the south to the north, which is partially realized. The problem with water will become more serious, of course, if the climate keeps changing and becomes drier in the future. Then what shall we do about it? The Chinese government has put the problem of future water supply as its top priority for the next 50 years.

NOVA: If you could know the answer to one question about the future, what would you want to know?

Ding: I think what we really want to learn is advanced technology. Many problems have been solved or averted by advanced technologies. No matter what the future will be, energy will be used up in the end. So we must develop new energies, such as hydrogen, solar, and wind power. We are very eager to learn how to make full use of these advanced technologies in order to improve our energy structure and environment.

Secondly, we are very keen on finding a better "life model" for developing countries. The life model will offer not only low emissions of carbon dioxide, but also a very comfortable life. The model that we call "low emission and high consumption" is what we really want to learn. We hope our economists will come up with this life model. The developing countries can't follow in the footsteps of advanced countries that have had high emissions and high consumption.

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