It is well known that water, H2O, is the single most important greenhouse gas. But water also plays a central role in determining the delicate balance of energy and mass that regulates the temperature of Earth. A wide range of predictions have been made regarding water in a warming climate, ranging from catastrophic droughts to increased monsoon rains and tropical storms. Conventional wisdom states that a warmer world is a wetter world. In a newly published paper in the journal Science, two researchers examine the Eocene (∼56 to 34 million years ago), looking for clues to the tropical climate–water relationship. Annual global temperatures during the Early Eocene Climatic Optimum (EECO) around 50 million years ago were as much as 12°C higher than modern values. The new results provide compelling evidence that the tropical engine of the water cycle was more active than predicted by current climate models.
Though Earth and its climate are billions of years old, climate science is still very young. So young that surprising new discoveries are constantly being made. One such discovery in the field of paleoclimatology—the study of Earth's climate in the distant past—was the uncovering of a period of great warming around 40 million years ago, in the middle of the Eocene Epoch. In the midst of a general cooling trend beginning at the end of the preceding Paleocene Epoch (~55 mya) there were a number of dramatic, sudden bursts of global warming. The most celebrate of these is the Paleocene-Eocene Thermal Maximum or PETM, when surface temperatures rose by 5-7°C. Recently, science has discovered another hot interval 15 million years later during the Middle Eocene. Named the Middle Eocene Climatic Optimum (MECO), it marked a time when deep sea temperatures rose about 4-5°C and atmospheric CO2 levels peaked. As new information is uncovered, climate scientists are scrambling to interpret what caused this second, more sustained period of warming and what it may mean for current climate conditions.
One of the scary predictions made about the impact of global warming is the extinction of many current species leading to a crisis in biological diversity. Like most of the speculative effects of global warming, this prediction is not only without scientific basis, it is precisely backward. A new paper in the journal Science, studying the impact of rapid global warming at the Paleocene-Eocene boundary, show that rapid tropical forest diversification occurred without plant extinction. Moreover, diversity seemed to increase at higher temperatures, contradicting previous assumptions that tropical flora will succumb if temperatures become excessive. The tropical rainforest was able to flourish under elevated temperatures and high levels of atmospheric carbon dioxide, in contrast to speculation that tropical ecosystems were severely harmed by the heat.
Recently this site posted an article about the extinction event 65.5 million years ago at the end of the Cretaceous period. That extinction coincided with a large asteroid impact at Chicxulub, Mexico, and occurred within the time of Deccan flood basalt volcanism in India. A new review article by 41 scientists, published in the March 5, 2010, edition of Science, was cited that summarized what science thinks it knows about the extinction. That article reinforced the single cause asteroid impact extinction scenario. Now, in an excellent example of how the scientific process works, and why scientific consensus is such a bogus term, the May 21 issue of Science has published a number of letters that take exception to the previous article's conclusions.
Although the story of the “Asteroid that killed the Dinosaurs” has become common knowledge for most people, there are still those scientists who back alternative causes of the end Cretaceous extinction even. Volcanoes, multiple meteor strikes and even widespread forest fires have been suggested as the cause of the dinosaurs' demise. The extinction event 65.5 million years ago did coincide with a large asteroid impact at Chicxulub, Mexico, and occurred within the time of Deccan flood basalt volcanism in India. A new review article by 41 scientists in the March 5 edition of Science runs down the list of what science thinks it knows about the extinction that set the stage for the age of mammals.
When it comes to climate, the early Paleogene period (~65-34 mya), at the start of the Cenozoic Era, had one of the most Eden like climates of the Phanerozoic Eon. As the Cenozoic progressed a cooling trend set in leading up to the formation of permanent ice caps and the Pleistocene Ice Age we are still experiencing. But before the world started to ice up our planet underwent one of the most dramatic bouts of global warming known to science—the Paleocene Eocene Thermal Maximum or PETM. Recently, global warming activists have tried to liken human CO2 emissions to the cause of the PETM, 55 million years ago. Is it true, that our actions may trigger a sudden sharp rise in global temperature?