2008 is forecast to be among the top 10 hottest years on record
 
This year is forecast to be among the top 10 hottest years on record, Britain's weather office said Thursday, despite a strong cooling effect predicted from the tropical weather phenomenon known as La Nina.

The global surface temperature in 2008 will rise 0.67 degrees above what climate scientists call the long-term average of 57.2 degrees, the Met Office said. The average is derived¹ by calculating the mean of surface temperatures registered globally between 1961 and 1990.

That would be enough to have it rank among the hottest years on record, although the Met Office said would be unlikely to beat the current warmest year of 1998, which was 0.94 degrees above the long-term average.

The Met Office said a powerful La Nina, the name given to the upwelling of large areas of cold water in the tropical Pacific Ocean, would probably keep 2008's temperature from breaking the global record. But it said the underlying² trend of higher and higher temperatures was likely to continue.

"Phenomena³ such as El Nino and La Nina have a significant influence on global surface temperature and the current strong La Nina will act to limit temperatures in 2008," said Chris Folland, a climate scientist at the Met Office's Hadley Center in Exeter, southwest England. "Sharply renewed warming is likely once La Nina declines."

The Met Office said the world's hottest years on record were 1995, 1997, 1998, and every year since 2000. Its global temperature records stretch back to 1850.

尽管热带气候“拉尼娜”现象会产生显著的降温作用，但专家预测2008年将成为有气象记录以来最热的十个年份之一。

据英国气象办公室本周四预告，2008年全球表面温度将超过长期平均温度0.67度（华氏温度）。气象科学家所公认的地球长期平均温度为57.2度，是1961年至1990年间各年份全球表面温度的平均值。

这个温度涨幅足以使2008年成为有气象记录以来最热的年份之一，不过英国气象办公室称，2008年不可能突破1998年的水平，1998年的全球气温比长期平均温度高出0.94度，成为目前最热的年份。

英国气象办公室称，2008年之所以不会破记录，是因为“拉尼娜”现象将对全球气温产生显著影响。该现象指的是热带太平洋的大面积冷水上涌（从而给全球气温带来的冷却作用）。但该机构称，全球温度越来越高的潜在趋势可能将继续。

位于英格兰西南部埃克塞特的英国气象办公室哈德里中心的气象专家克里斯•福兰德说：“‘厄尔尼诺’和‘拉尼娜’现象对于全球表面温度具有显著影响，而目前势力强大的‘拉尼娜’现象将对2008年的温度起到抑制作用。‘拉尼娜’现象一旦减弱，温度可能会迅速回升。”

据该气象机构介绍，有气象记录以来全球最热的年份为1995年、1997年、1998年，以及2000年后的每个年份。该机构的全球温度记录始于1850年。

Vocabulary:

on record:有记录以来的；记录在案的

upwell:上涌