摘要
Earth＇s climate has oscillated between greenhouse （warm） and icehouse （cold） modes throughout Earth history. At present, Earth is in the midst of an icehouse climate interval, despite the anthropogenic contribution to global warming and sea-level rise due to industrialization during the past two centuries. This led to a dramatic increase in atmospheric CO2, mainly caused by the extensive burning of fossils fuels. The Cretaceous （145 to 66 million years ago） is the youngest prolonged greenhouse climate interval in the Phanerozoic, marked by very high global mean temperatures with some extreme warming peaks （＇hothouse＇ or ＇supergreenhouse＇）, largely absence of permanent continental ice sheets, a mean global sea-level having been some 250 m higher than that of today, and levels of carbon dioxide 4 to 10 times higher than those of the pre-industrial era. If temperature will continue to rise as quickly as in the last three decades, we are close to being at the cusp to a new greenhouse climate interval facing quickly rising global sea-level and reaching atmospheric CO2 levels of the ＇Cretaceous supergreenhouse＇ in about the years 2190-2260 （Hay, 2011）. Evidence from Earth＇s history indicates that glacial-interglacial climate mode changes as well as past sea-level changes such as in the Cretaceous greenhouse occurred at rates orders of magnitude slower than observed at present. The recent rise in global sea-level in response to rising levels of atmospheric greenhouse gases, the associated global warm- ing, and the waning of continental ice shields is a primary concern for human society. To predict future sea-levels we need a better understanding of the record of past sea-level changes, especially in the greenhouse palaeoclimate modes. Therefore, understanding the Cretaceous palaeoclimate is essential for a more accurate prediction of future global climate, sea-level rise and environmental changes in a prospective ＇Cretaceous-like＇ greenhouse Earth.
Earth's climate has oscillated between greenhouse(warm)and icehouse(cold)modes throughout Earth history.At present,Earth is in the midst of an icehouse climate interval,despite the anthropogenic contribution to global warming and sea-level
基金
the financial support from the National Natural Science Foundation of China(NSFC)for Distinguished Young Scholar(Grant No.41525007)
an contribution to the IGCP609
a contribution of IGCP Project 609"Climate-environmental deteriorations during greenhouse phases:Causes and consequences of short-term Cretaceous sea-level changes"
