保罗·霍夫曼，一名哈佛大学退休的地质学教授，将在加州大学河滨分校举办一场免费的公开演讲，此次演讲的主题是“地球惊人的气候历史”。

　　长达数小时的演讲在2015年9月24日周三下午6:00开始，地点是加州大学河滨分校1200校园大道，学校推广中心的D室和E室。

　　地质记录表明地球气候在以戏剧性的、令人惊异的方式演变着。在他的演讲中，保罗·霍夫曼，一个野外地质学家，会分享他和那些发现这个变化的科学家以及努力阐扬气候变化理论的科学家互相学习的过程。他演讲的内容从气候变化成为一门科学的开端到他自己对雪球地球的研究。

　　霍夫曼曾经花了100多月绘制加拿大西北部和非洲西南部的岩层地图。他搜集地球历史上早期板块构造开始的证据。他因“雪球地球”而广为人知，雪球地球一系列理论认为大约在复杂动物最初形成的时候，全球都被冻结了。

　　霍夫曼出生在多伦多，在去维多利亚大学之前他的职业时光大部分在加拿大地质调查局度过，之后他又去了哈佛大学。他是美国国家科学院的外籍院士、美国艺术与科学学院的外籍荣誉院士，也是加拿大皇家学会的会员。

　　Paul Hoffman, a professor emeritus of geology at Harvard University, will give a free public lecture at the University of California, Riverside on “Earth’s Astonishing Climate History,” which is the title of the talk.

　　The hour-long talk will begin at 6 p.m., Thursday, Sept. 24, 2015, in Rooms D and E in the UCR Extension Center, 1200 University Avenue, Riverside, Calif. Parking is complimentary.

　　The geological record shows that Earth’s climate has changed in dramatic and surprising ways. In his talk, Hoffman, a field geologist, will share his fascination with the give and take between the scientists who discovered these changes and those struggling to develop theories of climate change. His story ranges from the beginnings of climate change as a science to his own involvement in the controversy over Snowball Earth.

　　Hoffman has spent more than 100 months mapping rock formations in northwestern Canada and southwestern Africa. He assembled evidence that plate tectonics began early in Earth’s history. He is widely known for the theory of Snowball Earth, an extraordinary series of global glaciations that occurred around the time the first complex animals evolved.

　　Born in Toronto, Hoffman spent most of his career with the Geological Survey of Canada before moving to the University of Victoria and then to Harvard University. He is a foreign associate of the U.S. National Academy of Sciences, a foreign honorary member of the American Academy of Arts and Sciences, and a fellow of the Royal Society of Canada.