As record-breaking fires burn across the western United States, president Donald Trump remains skeptical that climate change is a factor. Here he is Monday at a meeting with California officials. It'll start getting cooler, you just watch. I wish science agreed with you. Oh well I don't think science knows actually. Yet science has been sounding the alarm about climate change for a long time, says University of California Merced wildfire expert Leroy Westerling. We've been doing modeling and simulation for years now, that indicates that these really severe widespread fire seasons are coming. And we're seeing that emerge in real time. Wildfires need dry plants to burn. And climate change is increasing the supply he says. Studies show the west has warmed over the last century and warmer air dries things faster. That means even a normal year would be drier. But these have not been normal years he says. We had a drought for five years earlier in the 21st century here, that was unprecedented in probably the last thousand to twelve hundred years at least.
And warmer weather is melting the west's water reserves in the mountains. The region relies on winter snow accumulation to provide long-lasting water supplies, says wildfire expert Jessica Holovsky with the US Forest Service. We're seeing more precipitation falling as rain rather than snow. The snowpack isn't lasting as long with the higher temperatures. So it's running off earlier in the season. Leaving less water when the dry summer months arrive. And warmer drier conditions have helped tree-killing beetles multiply. All this has left roughly 150 million dead flammable trees standing in California's forests alone. But Hollowski says humans share the blame for the fires. Smaller fires used to happen naturally, which thinned out the forests. We have suppressed fire very effectively since world war II, that means there are more fuels now than there used to be. And so when fires do occur, there's more fuel to burn and they're more severe. Plus more people are living in areas that are prone to burn. So when fires do break out, they're more destructive and more costly. Conditions will get worse as the planet continues to warm Hollowski says. There's going to be more fire. You know, a kind of ballpark is maybe two to three times the annual area burned in the future. Scientists say this year's record-breaking fire season is just a taste of what's to come. Steve Baragona voa news
1. real time 实时
To make the training realistic the simulation operates in real time.
2. break out 爆发
The authorities have urged people to stock up on fuel in case hostilities break out.
随着破纪录的山火在美国西部燃烧，唐纳德·特朗普总统仍然对气候变化是一个因素持怀疑态度。特朗普总统星期一会见了加州官员 。天气会开始变凉的，你就看着吧 。我希望科学同意你的观点 。我不认为科学真的知道 。然而，加州大学默塞德分校的野火专家勒罗伊•韦斯特林表示，长期以来，科学界一直在为气候变化敲响警钟 。我们多年来一直在进行建模和模拟，这表明这些真正严重的大范围火灾季节即将到来 。我们看到了野火正在发生 。野火需要干燥的植物才能燃烧 。他说，气候变化正在使干燥的植物越来越多 。研究表明，西方在上个世纪已经变暖，而更温暖的空气会使干燥的速度更快 。这意味着即使是正常年份也会更干燥 。但他说，这几年都不太正常 。在二十一世纪早期，我们这里就发生了五年的干旱，这可能是过去一千年到一千二百年来前所未有的 。
更温暖的气候正在融化西部山区的水资源储备。美国林业局的野火专家杰西卡·霍洛夫斯基表示，该地区依靠冬季积雪来提供持久的供水 。我们看到更多的降水通过降雨，而不是以降雪的形式 。随着气温的升高，积雪不会持续太久 。所以积雪在这个季节的早些时候就消失了 。当干燥的夏季来临时，留下的水就少了 。更温暖干燥的环境有助于杀树甲虫的繁殖 。所有这一切只在加州的森林里就留下了大约1.5亿棵死掉的易燃树木 。但霍洛夫斯基说，人类是火灾的罪魁祸首 。过去，小规模的火灾通常是自然发生的，会使森林变得稀疏 。自从第二次世界大战以来，我们已经非常有效地抑制了火势，这意味着现在的燃料比过去更多 。所以当火灾发生的时候，有更多的燃料可以燃烧，火势更为严重 。另外，更多的人生活在容易被烧伤的地区 。所以当火灾发生时，它们的破坏性更大，成本也更高 。霍洛夫斯基说，随着地球继续变暖，情况会变得更糟 。会有更多的火灾发生 。你知道，未来每年燃烧的面积可能是一个棒球场的2到3倍 。科学家们说，今年创纪录的火灾季节只是对未来情况的小试牛刀 。美国之音新闻，史蒂夫·巴拉戈纳报道 。