咁都得 - 溫室效應?!
By Kwokman
Date: 18th May, 2009
地球氣溫不斷攀升導至兩極冰川融解是鐵一般的事實﹐科學家有可靠的數據支持﹐電影與電視積極提醒大眾溫室效應的惡果﹐不但每天詳盡報導最新動態﹐更繪形繪聲展現地球未來大部分陸地淹沒海水之下的慘況﹐一般認為兩極冰川融解會流出大量海水令水平線高升淹沒大地﹐一直以來亦有証據支持這觀點﹐但溫室效應將帶來的惡果未必如科學家與大眾的想像一般。
位於北極的亞拉斯加冰川連年失守﹐嚴重處如Juneau每年損失三十尺的冰川﹐不但沒有淹沒當地沿海低地﹐反而乾地不斷升上水面﹐陸地上升的速度令人費解﹐DeBoer先生五十年前遷居至當地﹐這五十年內由水平線以下升上海面的陸地足夠他在1998年興建了一個九洞的高爾夫球場﹐他現在有意願將高爾夫球場擴大至十八洞。
冰川融解在亞拉斯加衍生了前所未有的問題﹐卻不是大眾所指的海岸被淹沒的問題﹐現在的問題由新生陸地的擁有權﹐河流濕地乾固﹐至船隻如何往來﹐三文魚如何往上游產卵等等。有專家認為數十億噸的冰川融解﹐減輕了地面的沉重壓力﹐導至陸地高升﹐情況有如人離開了坐位﹐不再被壓的軟墊便回復原形﹐這說法真確與否實在難以証實﹐肯定又會發展成為一門新的理論或“科學”﹐冰川融解後﹐陸地不沉反升﹐這不是已經推翻了流傳了上千年的冰河淹沒大地的“科學”論証嗎?
現代人無論懂科學與否都迷信科學﹐而且傾向接受一些舉一反三的理論﹐事實鮮有這樣簡單﹐單看地球擁有最多的水﹐如果溫度下降體積便會收縮﹐即相同體積的水應該是越凍越重﹐如此推論﹐冰塊應該比水重﹐但事實並非如此﹐冰是浮於水面的﹐其實即使未結成冰的水﹐衹要低於攝氏四度﹐會變為越凍越輕﹐如水一般常見的物質﹐尚且不可以舉一反三的顯淺道理推論﹐何況肉眼看不見的物質?什麼二億年前的石頭﹐比天方夜談還要荒謬。
雖然科學對人類有很大用處﹐很多方面都改善我們的生活不少﹐但現代科學千瘡百孔﹐非常有限﹐不是絕對的真理﹐人應該善用這有限的科學而不是被這有限的科學支配。萬物都由神創造﹐洪水與末世都明明記載聖經裡﹐何以還要以有限的科學去反駁絕對的真理?溫室效應固然可怕﹐人類對大自然的損害不容置疑﹐但既然專家都不能解釋﹐應該是時間明白這些事情人是不能作主的﹐人破壞了神的創造﹐還滿有自信可以補夠﹐有人還沾沾自喜以為溫室校應可讓他們收復失地﹐打大旗幟繼續污染地球﹐後果無人能知﹐其實人類所知的衹是皮毛﹐卻橫衝直撞碰得一頭灰。
請參考以下紐約時報的報導。
May 18, 2009
As Alaska Glaciers Melt, It’s Land That’s Rising
By CORNELIA DEAN
JUNEAU, Alaska — Global warming conjures images of rising seas that threaten coastal areas. But in Juneau, as almost nowhere else in the world, climate change is having the opposite effect: As the glaciers here melt, the land is rising, causing the sea to retreat.
Morgan DeBoer, a property owner, opened a nine-hole golf course at the mouth of Glacier Bay in 1998, on land that was underwater when his family first settled here 50 years ago.
“The highest tides of the year would come into what is now my driving range area,” Mr. DeBoer said.
Now, with the high-tide line receding even farther, he is contemplating adding another nine holes.
“It just keeps rising,” he said.
The geology is complex, but it boils down to this: Relieved of billions of tons of glacial weight, the land has risen much as a cushion regains its shape after someone gets up from a couch. The land is ascending so fast that the rising seas — a ubiquitous byproduct of global warming — cannot keep pace. As a result, the relative sea level is falling, at a rate “among the highest ever recorded,” according to a 2007 report by a panel of experts convened by Mayor Bruce Botelho of Juneau.
Greenland and a few other places have experienced similar effects from widespread glacial melting that began more than 200 years ago, geologists say. But, they say, the effects are more noticeable in and near Juneau, where most glaciers are retreating 30 feet a year or more.
As a result, the region faces unusual environmental challenges. As the sea level falls relative to the land, water tables fall, too, and streams and wetlands dry out. Land is emerging from the water to replace the lost wetlands, shifting property boundaries and causing people to argue about who owns the acreage and how it should be used. And meltwater carries the sediment scoured long ago by the glaciers to the coast, where it clouds the water and silts up once-navigable channels.
A few decades ago, large boats could sail regularly along Gastineau Channel between Downtown Juneau and Douglas Island, to Auke Bay, a port about 10 miles to the northwest. Today, much of the channel is exposed mudflat at low tide. “There is so much sediment coming in from the Mendenhall Glacier and the rivers — it has basically silted in,” said Bruce Molnia, a geologist at the United States Geological Survey who studies Alaskan glaciers.
Already, people can wade across the channel at low tide — or race across it, as they do in the Mendenhall Mud Run. At low tide, the navigation buoys rest on mud.
Eventually, as the land rises and the channel silts up, Douglas Island will be linked to the mainland by dry land, said Eran Hood, a hydrologist at the University of Alaska Southeast and an author of the 2007 report, “Climate Change: Predicted Impacts on Juneau.”
When that happens, Dr. Hood said, the Mendenhall Wetlands State Game Refuge, 4,000 acres of boggy habitat, will be lost. “That wetland will have nowhere else to go,” he said.
In some places along the coast, the change has been so rapid that kayakers whose charts are not up-to-the-minute can find themselves carrying their boats over shoals that are now so high and dry they now support grass or even small trees.
In and around Juneau, “you can walk around and see what was underwater is turning into grassland and eventually into forest,” Dr. Hood said.
The topographical changes have threatened crucial ecosystems and even locally vital species like salmon.
“The lifeblood of our region has been salmon species and their return — and what is the impact when they return and the streams are dry?” said Mayor Botelho, who was born and raised in Juneau. “The salmon is bound to our identity as a region, who we are.”
He said he did not think that any species were in imminent danger, but added, “Anyone who is following climate change has to see that there are risks, perhaps great ones.”
Dr. Hood said many people in Juneau had hoped to maintain a waterway called Duck Creek as a salmon stream. But small streams like that “appear to be drying out,” he said. “There are a lot of people in town saying, Let’s just let it return to a greenway.”
Relative to the sea, land here has risen as much as 10 feet in little more than 200 years, according to the 2007 report. As global warming accelerates, the land will continue to rise, perhaps three more feet by 2100, scientists say.
The rise is further fueled by the movement of the tectonic plates that form the earth’s crust. As the Pacific plate pushes under the North American plate, Juneau and its hilly Tongass National Forest environs rise still more.
“When you combine tectonics and glacial readjustment, you get rates that are incomprehensible,” Dr. Molnia said.
In Gustavus, where Mr. DeBoer’s property is, the land is rising almost three inches a year, Dr. Molnia said, making it “the fastest-rising place in North America.”
In addition to expanding the golf course, Mr. DeBoer is negotiating with the Nature Conservancy to preserve some of the newly emergent land. He can do both, he said, because the high tide line has pushed almost a mile out to sea since his family first homesteaded on the property.
Where the shoreline is relatively flat, “it doesn’t take much uplift to make quite a bit of difference,” Mr. DeBoer said.
Kristin White, a 28-year-old schoolteacher who grew up in Haines, a town north of here, is from another family in the area whose real estate grew as land rose. When her father tried to sell some property in Haines, she said, “he had to have it resurveyed.”
But for Ms. White, who has vivid memories of visiting the Mendenhall glacier as a child, the gain in acreage has been bittersweet. Seeing the glacier retreat, she said, is “as if you lived in the Smoky Mountains and you were used to seeing certain peaks — and they disappeared. It’s just totally, totally sad.”