日本高清色视频在线视频在,国产香蕉97碰碰视频碰碰看,丰满少妇av无码区,精品无码专区在线,久久无码专区免费看,四虎欧美精品永久地址99,亚洲色无码一区二区三区

 
 
 

Global warming might threaten water supply

VOA 2012-11-13 09:48

分享到

 

Get Flash Player

Download

Global warming over the next century could significantly reduce the amount of winter snowpack in mountainous areas in the northern hemisphere, according to a new study published in Nature Climate Change.

Seasonal snowpack melt is an essential source of fresh water, and its loss could threaten drinking water supplies, agricultural irrigation and wildlife ecosystems.

Stanford University climate expert Noah Diffenbaugh led the study, which compares snowpack conditions across the northern hemisphere in the late 20th century with climate model projections for the next one hundred years.

Deceasing snowpack

Those projections are based on a range of scenarios which foresee a rise in average global temperatures of between two and four degrees Celsius.

The study concludes that average snow accumulation will decrease in most regions of the Western United States, Europe, Central Asia and the Himalayas, compared to historical patterns.

It projects that low and extremely low snow falls would exceed the lows of the later 20th century between 10 and 30 percent of the time with two degrees of warming.

And, Diffenbaugh says, "If the planet warms by 4 degrees Celsius, the United could experience snowpack accumulations below the levels of the late 20th century up to 80 percent of the years.”

The story is the same in other parts of the northern hemisphere, where snowpack is a natural, and critical, water reservoir.

Water worries

The study finds that an early spring melt would bring more water into the watershed sooner than usual, potentially flooding rivers, lakes and artificially dammed-river reservoirs.

And with less water available later in the season, chances for more wildfires, pests, and species extinctions increase.

Diffenbaugh says this timing would also exacerbate drought conditions when the demand for water is greatest.

“We can infer that should these physical climate changes occur in the future, that there would be impacts on water supply for agriculture and for human consumption and for natural ecosystems if the water storage and management systems are not adapted to those changes.”

According to climate models, extreme rain events are expected to increase as the planet warms.

However, Diffenbaugh says, that won’t change how the snowpack responds to climate change.

“Even where there are increases in extreme precipitation in the models, there are still robust decreases in the amount of snowpack on the ground at the end of the winter and in robust changes in the timing of runoff.”

California experiencing climate extremes

Frank Gehrke takes these findings very seriously. He heads the California Cooperative Snow Surveys program, which forecasts water flow from the mountains into man-made reservoirs that provide water for crops and people.

California is just one part of a broader picture discussed in the report. Since the state gets little rain in the spring and summer, Gehrke says timing of snow pack melt is critical.

He says he is seeing greater climate variation than ever before. “We’re having more extremes in terms of dry and wet years. We see that not only in our record, but also in discussions with a lot of other people who are studying climate.”

Gehrke says California water managers need better measurement tools and higher resolution aerial images of the state’s snowpack than were available in the Stanford study. For that, the state has turned to the U.S. space agency’s Airborne Snow Observatory.

Flying at altitudes of about 7,000 meters, the photo-reconnaissance aircraft capture detailed images of mountain snowpack over a wide area, allowing scientists to more accurately compute the entire volume of water in a given watershed.

The NASA flights will also measure how much sun is reflected from the snowpack, which can indicate how fast it is likely to melt.

相關(guān)閱讀

New 007 movie reveals Bond's inner demons(視頻)

Breathe Carolina re-releases "Hell is What You Make it"(視頻)

Obama victory driven by economy, turnout

New York officials work to curtail price gouging(視頻)

(來(lái)源:VOA 編輯:Julie)

 

分享到

中國(guó)日?qǐng)?bào)網(wǎng)英語(yǔ)點(diǎn)津版權(quán)說(shuō)明:凡注明來(lái)源為“中國(guó)日?qǐng)?bào)網(wǎng)英語(yǔ)點(diǎn)津:XXX(署名)”的原創(chuàng)作品,除與中國(guó)日?qǐng)?bào)網(wǎng)簽署英語(yǔ)點(diǎn)津內(nèi)容授權(quán)協(xié)議的網(wǎng)站外,其他任何網(wǎng)站或單位未經(jīng)允許不得非法盜鏈、轉(zhuǎn)載和使用,違者必究。如需使用,請(qǐng)與010-84883561聯(lián)系;凡本網(wǎng)注明“來(lái)源:XXX(非英語(yǔ)點(diǎn)津)”的作品,均轉(zhuǎn)載自其它媒體,目的在于傳播更多信息,其他媒體如需轉(zhuǎn)載,請(qǐng)與稿件來(lái)源方聯(lián)系,如產(chǎn)生任何問(wèn)題與本網(wǎng)無(wú)關(guān);本網(wǎng)所發(fā)布的歌曲、電影片段,版權(quán)歸原作者所有,僅供學(xué)習(xí)與研究,如果侵權(quán),請(qǐng)?zhí)峁┌鏅?quán)證明,以便盡快刪除。

中國(guó)日?qǐng)?bào)網(wǎng)雙語(yǔ)新聞

掃描左側(cè)二維碼

添加Chinadaily_Mobile
你想看的我們這兒都有!

中國(guó)日?qǐng)?bào)雙語(yǔ)手機(jī)報(bào)

點(diǎn)擊左側(cè)圖標(biāo)查看訂閱方式

中國(guó)首份雙語(yǔ)手機(jī)報(bào)
學(xué)英語(yǔ)看資訊一個(gè)都不能少!

關(guān)注和訂閱

本文相關(guān)閱讀
人氣排行
搜熱詞
 
 
精華欄目
 

閱讀

詞匯

視聽(tīng)

翻譯

口語(yǔ)

合作

 

關(guān)于我們 | 聯(lián)系方式 | 招聘信息

Copyright by chinadaily.com.cn. All rights reserved. None of this material may be used for any commercial or public use. Reproduction in whole or in part without permission is prohibited. 版權(quán)聲明:本網(wǎng)站所刊登的中國(guó)日?qǐng)?bào)網(wǎng)英語(yǔ)點(diǎn)津內(nèi)容,版權(quán)屬中國(guó)日?qǐng)?bào)網(wǎng)所有,未經(jīng)協(xié)議授權(quán),禁止下載使用。 歡迎愿意與本網(wǎng)站合作的單位或個(gè)人與我們聯(lián)系。

電話:8610-84883645

傳真:8610-84883500

Email: languagetips@chinadaily.com.cn

<strong id="xdwva"><div id="xdwva"></div></strong>
<label id="xdwva"></label>

<thead id="xdwva"></thead>
    <label id="xdwva"></label>

  1. 日本高清色视频在线视频在,国产香蕉97碰碰视频碰碰看,丰满少妇av无码区,精品无码专区在线,久久无码专区免费看,四虎欧美精品永久地址99,亚洲色无码一区二区三区 久久九九久精品国产日韩经典 国产国语国拍精品 啊v在线观看高清无码 视频一区二区欧美 久久精品爱爱唉爱