科學家：地球邁入新地質時代 ─ 人類世 - 地球科學討論

科學家：地球邁入新地質時代 ─ 人類世（Anthropocene） 2010.03.28 中央社

http://tw.news.yahoo.com/article/url/d/a/100328/5/22vxc.html
譯者：中央社蔡函岑


科學家宣稱，地球已進入新的地質時期，即新人類紀元。人類已對地球造成非常廣
泛而前所未見的變化，我們可能正邁入地質史上的新階段。

據英國「每日電訊報」（Daily Telegraph）報導，科學家認為，由於環境污染、人
口暴增、都市化、人類移動、大量採礦、以及化石燃料的使用；人類已徹底改變地
球生態，勢必會影響到未來數百萬年。

專家憂心，人類對地球造成的傷害，將導致地球史上第六次大規模物種滅絕，數以
千計的動、植物將不復存在。

這個稱為「人類世」（Anthropocene）的新時代，將成為單一物種行為所形塑的的
第一個地質時期。「人類世」原意是指新人類。

儘管科學家早已非正式的使用「人類世」一詞長達10多年，科學界正考慮要將該詞
正式端上檯面。

專家已組成工作小組，負責蒐集各種證據，證明地質時代將從現今的「全新世」（
Holocene）進入「人類世」。

專家小組將考量人類活動對地球造成的影響，包括生物多樣性、岩石結構、以及污
染和採礦等其他因素的衝擊。

專家小組希望未來三年內能夠將研究成果提交到「國際地質科學聯合會」（Inter-
national Union ofGeological Sciences, IUGS），再由該會裁定地球是否已進入
新地質時期。

這項理論是由一科學家小組所提出，該小組成員包括諾貝爾化學獎得主克魯岑（Paul
Crutzen）。

科學家小組在研究中作出以下結論：「人類世在人類史上和地球史上都代表著新的
發展階段，此時自然力量和人類力量緊密相連，因而兩者命運休戚與共。就地質學
而言，這是地球史上相當顯著的事件。」


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Not Set in Stone Astrobiology Magazine/ Geology

Summary:
For the past 12,000 years, the Earth's climate has been relatively stable and
hospitable. That time - the Halocene epoch - may be coming to an end as a new
period in geologic history begins. Welcome to the Anthropocene - the "human
epoch".

http://www.astrobio.net/index.php?option=com_retrospection&task=detail&id=3446


Welcome to the Anthropocene – the “human epoch.” Geological time may seem
set in stone, and certainly it has been (as far as we've defined it) for the
past 12,000 years in the Holocene.

But the Holocene's relatively stable interglacial climate, so hospitable
that it allowed the rise of human civilization, seems to be coming to a close.
Geologic epochs are typically defined by distinctive changes in sedimentary
layers. So what makes these days geologically different? Well, long after
we're all gone, a million years into the future, some intelligent life would
be able to see clear signs of human activity in the same layers of soil
across the globe.


http://www.astrobio.net/blog/wp-content/uploads/2010/03/Anthropocene-
Zalasiewicz-GSA1feb08f1.gif
Environmental changes during the Holocene Epoch show the beginnings of
dramatic spikes, marking the would-be Anthropocene. Graph courtesy of
authors Jan Zalasiewicz, et. al.


To show up, the disturbance has to be on a massive scale, and in fact it
is. Climate change, mass extinctions, soil erosion, cleared land, pollution,
radioactive isotopes from nuclear tests, sea level rise: all these human-
induced changes are producing clear patterns of change that are being
documented in the soil.

Anthropocene has been used informally, starting with Nobel Prize winning
chemist Paul Crutzen, who in 2002 coined the phrase quite unwittingly at a
conference where, according to his quote in the Encyclopedia of Earth:

“… someone said something about the Holocene. I suddenly thought this
was wrong. The world has changed too much. So I said: ‘No, we are in
the Anthropocene.’ I just made up the word on the spur of the moment.
Everyone was shocked. But it seems to have stuck.”

In February 2008, a GSA Today article (a monthly publication by the Geological
Society of America) made the case for making the anthropocene epoch official
among geologists. It nicely tracks the way human activity has made its mark
in the geologic record, from mid-Holocene biotic evidence of weed pollen and
the remains of cultivated plants in human settlement areas, to a layer of lead
pollution that has settled in the polar ice caps and peat bog deposits from
the Greco-Roman times onward.

The authors write:

“Human activity then may help characterize Holocene strata, but it did
not create new, global environmental conditions that could translate
into a fundamentally different stratigraphic signal. ”

That only began to happen during the Industrial Revolution, which resulted in
dramatic erosion due to expanded agriculture and construction, the damming of
most major rivers thereby changing sedimentary patterns, waves of extinction
and the replacement of natural vegetation with agricultural monocultures,
ocean acidification, and, of course, a spike in carbon dioxide levels.


http://www.astrobio.net/images/galleryimages_images/Gallery_Image_6224.jpg
Change in sea surface pH caused by anthropogenic CO2 between the 1700s and
the 1990s. Credit: Wikipedia Commons


A temperature rise of between 2 degrees to 11.5 degrees Fahrenheit, as
predicted under climate change models, hasn't been seen since the Tertiary
period 66 million years ago, when mammals replaced reptiles as the predominant
vertebrates, the article states.

The first step towards making Anthropocene official is to select a date when
it begins — not exactly an easy task considering that human impact hasn't
be uniform across the globe throughout history. Does it make sense to start
at the launch of Industrial Revolution in the West?

One clear sign that we're already deep into the Anthropocene is that we talk,
not only about human destruction of the Earth, but also contemplate ways to
fix it through geo-engineering. Wired this month ran a book review of Hack
the Planet by Eli Kintisch about embracing our “God role” since things have
so changed so much that “stewardship” is no longer an option.




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