Saving Plants to Save Ourselves: The Shenzhen Declaration
Our planet consolidated into its present form about 4.5 billion years ago, with life appearing at least 3.9 billion years ago. The photosynthetic group of bacteria known as Cyanobacteria began producing oxygen about 2.7 billion years ago, with oxygen reaching present or even higher levels around the start of the Cambrian Period, 541 million years ago, about the same time that multicellular life first appeared. Animals, plants, and fungi colonized the land and began to diversify about 450 million years ago, with seed plants appearing about 370 million years ago and angiosperms some 135 million years ago. The ancestors of both dinosaurs and mammals appeared about 200 million years ago. The fourth great extinction occurred at about the time dinosaurs and mammals first appeared, with the last dinosaurs disappearing at the time of the fifth and last great extinction, at the end of the Cretaceous Period about 66 million years ago. Mammals then began to diversity, with primates, the mammalian order of which we are members, appearing about 55 million years ago. It is estimated that about 99% of all kinds of organisms that ever existed on earth are extinct, but when our ancestors diverged from the African apes about 6-8 million years ago, they did so in a world of biological richness, with perhaps 12 million species of eukaryotes and countless millions of species of prokaryotes supporting the functioning of the global ecosystem. The oldest fossils we know of our genus, Homo, date from about 2.8 million years ago, the oldest of our species, Homo sapiens, from about 200,000 years ago; these are both from Africa, with Homo sapiens migrating to Eurasia about 60,000 years ago. Therefore we are very new on Earth, but our activities have become devastating to our continued existence and that of other organisms as well.
The human development of agriculture as a main source of food about 10,000 years ago led to an explosion of our numbers from about 1 million people then to 7.4 billion today, projected to grow to 9.9 billion by mid-century, 33 years from now. This has made us an ecological force so great that we can be said to have entered the Anthropocene Period, one in which our actions will determined the fate of everything on Earth. For example, our bodies and those of our domestic animals now constitute 95% of all mammalian biomass on our planet. We are estimated to be consuming on a continuing basis about 164% of the planet’s sustainable productivity, with some of us rich and many poor (www.footprintnetwork.org) . Like all organisms, we depend on the functioning of the global ecosystem for every aspect of our lives, and yet we are currently tearing it apart. Extinction is currently taking place at a rate 1,000 times or more greater than it has since the end of the Cretaceous Period 66 million years ago, so that as many as half of the estimated 12 million species of eukaryotes existing now are likely to have disappeared from nature by the end of the 21st Century, and we shall not even have recorded most of them.
Plants, and photosynthesis in general, do not receive the attention they deserve, and if we want to attain global sustainability, we shall have to work much harder to gain the knowledge that we need to save ourselves and to apply it to the maintenance of a sustainable world. We shall need to emphasize field studies in order to understand better the functioning of our globe. We have little or no knowledge about the majority of species of plants or other organisms on earth, despite our living during the last decades when many of them will exist. Nations and peoples have become starkly unequal, women and children often neglected or suppressed, and yet we are in danger of perishing together unless we do much better in these respects. We need to learn to cooperate with and love one another while there is still time to do so. We must attain a level population, equality between peoples, and better technologies while we still can do so. Plants, the subject of this Congress, and agriculture must receive greater attention since we depend so clearly and completely on them. Let us make this Congress a time of commitment to do better and resolutely seek a sound and sustainable future for all people.