氣候變遷的全球解決方案（上）

China has one fifth of the world’s population, has maintained double digit economic growth for most of the last 3 decades, and is preparing to become the largest single national economy in the world. Because of its increasing international clout, its growing emissions and the desire to apportion blame, China has been criticized for contributing to our world’s growing environmental challenges including sometimes being blamed for an outsize portion of human impact on climate change. China certainly does have the responsibility to be environmentally responsible to its people, to all people everywhere and to the planet. But China is not alone in this responsibility and it is unfair to single China out without analyzing how other countries are responding to this crisis. This is a truly global issue and it must be dealt with by international consensus and knowledge led action. I would go further to suggest that although the outcome will only be known in the future, in some ways China is beginning to demonstrate some of the characteristics of leadership in this matter.

Globally the scientific community has reached consensus that human activity, has caused and is causing, disruption to the natural ecosystem, with extensive, predictable and increasingly catastrophic results. Currently, the focus is on the impact of carbon disequilibrium on the Earth’s atmosphere and climate. This is most often expressed as the wanton emission of CO2 and other gases that cause the “Greenhouse Effect”, (where sunlight can penetrate but heat is trapped in the atmosphere). Many international panels have helped to define the situation. The Intergovernmental Panel on Climate Change (IPCC) and Al Gore shared the Nobel Prize forewarning about the danger posed by human induced climate change. The Millennium Ecosystem Assessment presented an even more comprehensive study that documents human impact on the Earth’s Ecosystem including but not limited to atmospheric disruption. The Stern Report to the UK Government charted the linkages between ecology and the economy. All these reports are unanimous that without a paradigm shift humanity faces an uncertain future at best. The worst case is so bad it is difficult to contemplate or describe. There are some models that lead to conditions where human life would no longer be viable and the human species goes extinct.

That such massive ecosystem degradation exists attests to the selfish and wasteful behavior of the billions of people on Earth. Yet the guilt and the consequences have not been equally felt. The world is fairly evenly divided into those who have acquired large amounts of the earth’s wealth and those who are denied access to it. So although humanity is extracting benefits from the earth at astonishing rates we have also created a social and economic system that is terribly unfair. The poverty and disparity and the ecological damage are deeply interrelated.

No amount of words can do justice to this situation because it is not theoretical but physical. In order to overcome our impacts and restore equilibrium to natural systems we will have to “physically” restore the systems to functionality. Given the fact that our behaviors are what has caused the dysfunction this will require what the Stern Report called “Major non-marginal change”. We who are alive today are challenged to understand this and to address it. How well we do this will determine what the future will be like. Will we respond to the challenge? How are we to respond? Will we be able to change our behaviors to end the negative impacts? Will we be able to stretch our imaginations sufficiently to envision a way forward to a sustainable future?

The Opportunity within the Challenge

Africa seems to have become linked with poverty in public collective consciousness worldwide. One hears a great deal about poverty and Africa, but very little about African wealth. Many people in Africa and other continents just “know” that Africa is poor and many believe there is nothing that can be done about it. But is this impression fair? And if not, what are the factors that determine whether Africa is wealthy or poor? If we knew this, might there be a strategy that could direct positive physical action toward addressing the underlying causes of poverty? As certain trends converge, such as: climate change, population growth, biodiversity loss, desertification, and fresh water stress, Africa may be seen to represent the place that is most affected by these problems. But Africa therefore is also the place with the largest potential on the planet to address these issues.

As I have traveled, filmed and studied in Uganda, Tanzania, Rwanda, Ethiopia and Kenya, I have been extremely surprised at how wealthy Africa could be. So why isn’t it? At its most fundamental level the question of whether Africa is poor or wealthy seems to me to hinge on ecosystem function. Basically this means, whether there is tree cover on the mountains and grass cover on the savannahs, whether the rainfall infiltrates and is retained where it falls, and whether carbon and other nutrients are naturally recycled in the biomass and soil organic matter, or not. Naturally there are other considerations but they can be shown to be secondary to these fundamental determinants.

I first observed this phenomenon in China’s Loess Plateau where the situation is amazingly similar. Having lived in China for most of the last 3 decades and having observed as “The Middle Kingdom” emerged from the poverty that plagued it for a century, I have personally seen that poverty and ecological degradation are linked. I have also seen that things don’t have to just get worse. If you employ enlightened principles, policies and practices then things can and do get much better. I wouldn’t suggest that China has no problems but China is a good example that fundamental change is possible and that it is possible to end poverty.

My research has also shown that ensuring functional ecosystems is not simply in the interest of the poor people who live in degraded areas. Given what we now know of climate change and the interconnectedness of global ecosystems it is logical to conclude that the future for everyone on Earth will be determined by functional ecosystems on a planetary scale. Using current criteria to view Africa, the situation seems very bad indeed. But if people worldwide valued ecosystem functions and decided to collectively restore degraded ecosystems wherever they were, then the local people who did the work and who must continuously protect the restored ecosystems, could be rewarded for their service to humanity and future of the planet. Looking at Africa from this perspective the situation is far from hopeless. This makes Africa one of the most important places for the future and its people among the most useful and needed in the world.

As one travels through the Ethiopian Highlands in the dry season, the abundance of water is not foremost on the mind. For most of the year, people and animals travel long distances to get water. Everywhere, lines of women and children carrying yellow plastic containers are walking either to or from a water source, or waiting in line for their turn to access the trickle coming out of a pipe, or to dip their pale in a shallow dirty stream. For many of these people, getting water, together with gathering fuel wood, can take up most of the day. This has been going on for such a long time that people have determined that this is natural and inevitable. In this world of scratching out a living, things just get worse. We badly need to tell the truth about this situation. This type of labor is an anachronism, it is pointless and destructive, as long as we allow this to continue there will be no way to restore ecosystem function.

There is a keen awareness by everyone here that the rainy season and the dry season are very, very different. What is less understood is that over wide areas in Africa and elsewhere worldwide, the extreme dryness during the dry season is not a natural phenomenon or that it can be reversed. What has happened here is that human activities have put pressure on fragile ecosystems, disrupting the natural infiltration and retention of water. Our impact began by reducing or removing the vegetation cover that had developed over evolutionary time. Without each generation of vegetation (biomass) laying down its body to nurture the next, there is little or no organic matter (necromass) in the soils. The plant root systems that penetrated and broke up compacted soils are no longer there. Microbes and fungus that lived among roots and fed on the soil organic matter are lost. Nutrients in the soil and soil stability are visibly reduced, just look at the brown color of the streams carrying away the soil and its fertility.

Photographic evaluation of typical lands in the Northern Highland regions of Ethiopia reveal a very high degree of degradation over vast areas. The United Nations Food and Agriculture Organization (FAO) rate the area as very severely degraded with a few areas that are only rated severely degraded. The widespread assumption is that the Ethiopian Highlands are arid or semiarid lands. But is this assumption true? The scientific definition of arid or semi-arid is that the “Evapotranspiration” rate or the rate at which moisture is lost due to a mixture of evaporation and respiration is greater than the rainfall. In discussions with scientists studying Natural Resources at Bahir Dar University, I learned that much of the highland region near Bahir Dar gets approximately 1,800 millimeters of rainfall per year. This is a great abundance of water, equal to what is needed by the great Rain Forests of the world.

Indeed, where the land remains more or less unchanged, such as on the islands in Lake Tana, the natural habitat is a diverse forest of large trees including cordia, cedar, ficus, acacia, forest coffee and other indigenous trees and bushes. These relatively natural ecosystems have coexisted with churches and monasteries and a population in the thousands for many centuries, showing that the presence of humans does not necessarily have to degrade the environment. In the forests on the islands in Lake Tana there is never a thought that this might be an arid or semi-arid area. Even in the dry season there is soil moisture and relative humidity in the air.

Beyond such special protected places like the islands in Lake Tana, much of the landscape appears to be desert or near desert, especially in the long dry season. There is no mystery about the causes, the reasons are continuously on display, day after day, year after year, generation after generation. Trees and brush are cut continuously for fuel wood. Animal manure is collected and burned. Biomass burning from these sources represents 94 % of the energy used in Ethiopia. Primitive plowing consistently exposes the soil to the sun, wind and rain. Goats, sheep and cattle, together with their herders, wander aimlessly, compacting the soil with their hooves as they search for the last grasses and bushes to eat, pulling the plants out by the roots further exposing the soils and further reducing vegetation. These are the behaviors that have caused the decline and collapse of numerous civilizations throughout human history. That sub-Saharan Africa in particular is experiencing poverty and famine is predictable and measurable. If these fundamental causes are not dealt with there is no way to rehabilitate the environment or improve the economy. Africa needs a paradigm shift that will alter the ecology, economy and the psychology in one moment. From that moment on Africa would be launched on a new development trajectory, one that leads to sustainable ecosystems and Africans would then have all the opportunities of life open before them.

I think that modern people in many cultures around the world often imagine that we are political or economic beings and sometimes would like to forget that we are mammals, living in symbiosis with other life forms. But we are born, live and die like other creatures and we are governed by the same natural laws. During the rainy season if the rain does not infiltrate and is not retained, then during the dry season the land and the air will be very dry. When this is repeated, year after year, generation after generation, this desiccated state seems to become the norm. But from a scientific perspective any measurements that determine places with high rainfall to be “Arid” or “Semi-Arid” could be suspected of observing and measuring dysfunction. In other words, without vegetation cover and natural infiltration and retention of water their figures are correct. But if you were to measure functionality in places like this a very different result would accrue. From a scientific perspective it would seem to be of paramount importance to know whether reversing the trends toward de-vegetation and ecosystem dysfunction would still lead to arid and semi-arid designations for these areas.