William Calvin       . . . is a theoretical neurophysiologist at the University of Washington, Seattle, who also trained in physics. Most of his nine books are written for general readers, including How Brains Think, in the widely-translated Science Masters series. The Throwing Madonna, The Cerebral Symphony, and The Ascent of Mind are about brains and evolution, The Cerebral Code explores Darwinian processes that operate on the time scale of thought and action. Dr. Calvin. s interest in weather intersects with his thinking about human evolution.

3:10

The earth's climate has experienced abrupt temperature changes that last for decades and sometimes millennia. It's happened repeatedly. And today's global warming could very well destabilize the North Atlantic current, triggering a return to Ice Age climate conditions in the Northern Hemisphere and much of the rest of the world. Agriculture worldwide would be profoundly impacted. Distribution of what food remained would be hugely disrupted. People in cities would starve. After a catastrophic . downsizing. of the human population, we. d be left with a lot of little despotic governments, everyone hating their neighbors with good cause -- a world full of Yugoslavias. That's the bad news.

The good news, according to Dr. William H. Calvin, is that we stand a very good chance of heading off the mayhem an abrupt climate flip-flop. would trigger, of slowing down or stopping a long overdue switch to drought and colder temperatures. Dr. Calvin is a theoretical neurophysiologist at the University of Washington, trained in physics as well as physiology. He is internationally known for his studies of the complex systems found in the human body and brain. Most of his nine books are about brains and evolution. Dr. Calvin. s interest in weather intersects with his thinking about human evolution.

Dr. Calvin is still deeply concerned about global warming, but he believes today's science and technology may already be up to the task of avoiding an abrupt drop in temperature, triggered by changes in the North Atlantic Current. The challenge? Keep the North Atlantic Current flowing. It's really very simple physics, according to Dr. Calvin. The North Atlantic Current, also called the Gulf Stream, keeps Europe unnaturally warm by carrying heat up from the tropics. It also affects the "salt conveyer. in all the world. s oceans. If disrupted by the effects of global warming, the Current could abruptly stop. It has done so repeatedly over millions of years, leaving Europe high and cold.

The time for good science is now, pleads Dr. Calvin. What needs doing if we. re going to avoid pulling the climate trigger on ourselves? Start! Redouble our current scientific efforts. Given North America and Europe. vulnerability, NATO and the European Union are plausible champions. Gather a great deal more information about the North Atlantic Current. Generate more and better computer models of the ocean/atmosphere/biosphere. Test alternative interventions where we can afford to make beginners. mistakes. Pay attention!

Agriculture and ready access to its fruits made civilization possible. Decades of disruption to agriculture, caused by sudden climate change, could destroy civilization as we know it. Civilization's children -- science and technology -- hold the key.

Hunter-gatherers could move when the weather changed. London cannot.

Conversation 1

Dr. Calvin tells Paula Gordon, Bill Russell and guests at The Commerce Club what science has discovered about rapid global climate changes and their devastating effects. He describes the abruptness (10 to 20 years) of the cooling that could be 20 times colder than the so-called "Little Ice Age" which spanned the years 1300 to 1890. He describes how thoroughly such a cooling would disrupt civilization as we know it.

  8:34

Conversation 2

Dr. Calvin describes the mechanism by which global warming could trigger a drastic and rapid change in the weather. He explains why Europe, on a latitude with Canada, is at particular risk because of the way the North Atlantic Current warms it. He tells why he thinks the mass media has missed the stories of abrupt cooling and warming and has failed to report the growing historical record of such changes happening every several thousand years. He describes the "Nordic Seas heat pump" and the vulnerable downwellings in the ocean. s surface and outlines how easy it might be to stabilize the threat of which he warns us.

  9:26

Conversation 3

The prospect of an abrupt cooling is the most disastrous possible consequence yet of global warming. Dr. Calvin describes the importance of heeding the good predictions computer climate models make. He tells us why he believes the prospects are "very good" that we will have a substantial change of temperature with all the consequences that change will have for plants, the animals that live on plants and agriculture. He relates that to the global cooling which scientists believe the current warming trends may trigger. Once begun, the cooling would be very hard to reverse. He shows us why NOW is the time to investigate interventions. There may, in fact, even be simple solutions based on present day technology. Dr. Calvin gives examples, warns against fatalism, and strongly urges a lot more . good science. so we can invent efficient solutions.

  9:46

Conversation 4

Given Europe. s vulnerability, Dr. Calvin offers suggestions for European organizations that might take the lead. He warns this is not Europe. s problem, the entire world is vulnerable. He tells how agriculture would be affected, worldwide, if the climate dropped to Ice Age temperatures, whether or not the change lasted long enough for significant ice accumulation. He expresses concern that Europeans know as little about the threat as do Americans.

Dr. Calvin describes the true composition of the ocean (not homogeneous) and the importance of understanding how non-linear systems like climate work. He describes the role of the North Atlantic as part of a worldwide conveyer of salt water, part of the much larger relationship between the ocean and the atmosphere. While climate is a complicated system, Dr. Calvin describes other complicated systems which biologists do understand.

  10:36

Conversation 5

Dr. Calvin describes how his work as a physiologist helped him learn from oceanographers. He describes his 35 years of considering what Ice Ages had to do with human evolution and what triggered the quadrupling of the human brain. He describes the advantages hunter-gatherers had over present day humans faced with abrupt climate changes and the advantages of animals which do not over specialize. Dr. Calvin tells why there is no evolutionary "silver lining" to humans facing another abrupt climate change.

  10:26

Conversation 6

Dr. Calvin describes the scientific understanding he thinks we need. He reminds us that climate stability helped create civilization and urges us now to use civilization to stabilize the climate if we are to save ourselves from the thoroughly dreary future he suggests is the alternative. He reminds us of the enormous chances humans take as we continue to pour carbon dioxide into the atmosphere.

  5:54

Acknowledgements