我们还面临另一个幽灵，那就是非线性的“气候引爆点”，这会带来许多严重得多的变化。“气候引爆点”的一个例子就是永久冻土层的融化。永久冻土层经过千年的累积形成，其中包含了巨量的冻僵的有机物。如果冻土融化，微生物就将广泛繁殖，使得冻土层中的有机物残骸快速腐烂。冷冻后的生物和冷冻前的生物，它们在生物学特性上的差异，我们都很熟悉。在冷库中，冷冻食品在经过长时间保存后，依然可以食用。但是，一旦解冻，食品很快就会腐烂。一个腐烂的永久冻土层，将释放出多少甲烷和二氧化碳？即使只有一部分的碳被释放出来，可能也比我们从工业革命开始释放出来的所有温室气体还要多。这种事情一旦发生，局势就失控了。
We also face the specter of nonlinear “tipping points” that may cause much more severe changes. An example of a tipping point is the thawing of the permafrost. The permafrost contains immense amounts of frozen organic matter that have been accumulating for millennia. If the soil melts, microbes will spring to life and cause this debris to rot. The difference in biological activity below freezing and above freezing is something we are all familiar with. Frozen food remains edible for a very long time in the freezer, but once thawed, it spoils quickly. How much methane and carbon dioxide might be released from the rotting permafrost? If even a fraction of the carbon is released, it could be greater than all the greenhouse gases we have released to since the beginning of the industrial revolution. Once started, a runaway effect could occur.
气候问题是我们的经济发展在无意中带来的后果。我们太依赖化石能源来维持我们的冬天取暖、夏天制冷、夜间照明，我们用它来长途旅行、环球观光。能源是我们享受的经济繁荣的基础，我们不可能放弃经济繁荣。美国人口占全世界的3%，但是我们消耗全世界25%的能源。与此形成对照，全世界还有16亿人没有电，数亿人依靠燃烧树枝和牲畜的粪便来煮饭。发展中国家的人民享受不到我们的生活，但是他们都看在眼里，他们渴望拥有我们拥有的东西。
The climate problem is the unintended consequence of our success. We depend on fossil energy to keep our homes warm in the winter, cool in the summer, and lit at night; we use it to travel across town and across continents. Energy is a fundamental reason for the prosperity we enjoy, and we will not surrender this prosperity. The United States has 3 percent of the world population, and yet, we consume 25 percent of the energy. By contrast, there are 1.6 billion people who don’t have access to electricity. Hundreds of millions of people still cook with twigs or dung. The life we enjoy may not be within the reach of the developing world, but it is within sight, and they want what we have.
这就是新的挑战。我们把全世界作为一个整体，要缓解气候变化带来的后果，至少100年才能实现，我们到底愿意付出多少？代际责任深深植根于所有文化中。家长努力工作，为了让他们的孩子有更好的生活。气候变化将影响整个世界，但是我们的天性使得我们只关心个人家庭的福利。我们能不能把全世界看做一个整体？能不能为未来的人们承担起责任？
Here is the dilemma. How much are we willing to invest, as a world society, to mitigate the consequences of climate change that will not be realized for at least 100 years? Deeply rooted in all cultures, is the notion of generational responsibility. Parents work hard so that their children will have a better life. Climate change will affect the entire world, but our natural focus is on the welfare of our immediate families. Can we, as a world society, meet our responsibility to future generations?
虽然我忧心忡忡，但是还是对未来抱乐观态度，这个问题将会得到解决。我同意出任劳伦斯·伯克利国家实验室主任，部分原因是我想招募一些世界上最好的科学家，来研究气候变化的对策。我在那里工作了4年半，是这个实验室78年的历史中任期最短的主任，但是当我离任时，在伯克利实验室和伯克利分校，一些非常激动人心的能源研究机构已经建立起来了。
While I am worried, I am hopeful we will solve this problem. I became the director of the Lawrence Berkeley National Laboratory, in part because I wanted to enlist some of the best scientific minds to help battle against climate change. I was there only four and a half years, the shortest serving director in the 78-year history of the Lab, but when I left, a number of very exciting energy institutes at the Berkeley Lab and UC Berkeley had been established.
能够成为奥巴马施政团队的一员，我感到极为荣幸。如果有一个时机，可以引导美国和全世界走上可持续能源的道路，那么这个时机就是现在。总统已经发出信息，未来并非在劫难逃，而是乐观的，我们依然有机会。我也抱有这种乐观主义。我们面前的任务令人生畏，但是我们能够并且将会成功。
I am extremely privileged to be part of the Obama administration. If there ever was a time to help steer America and the world towards a path of sustainable energy, now is the time. The message the President is delivering is not one of doom and gloom, but of optimism and opportunity. I share this optimism. The task ahead is daunting, but we can and will succeed.
我们已经有了一些答案，可以立竿见影地节约能源和提高能源使用效率。它们不是挂在枝头的水果，而是已经成熟掉在地上的，就看我们愿不愿意捡起来。比如，我们有办法将楼宇的耗电减少80%，增加的投资在15年内就可以收回来。楼宇的耗电占我们能源消费的40%，节能楼宇的推广将使我们二氧化碳的排放减少三分之一。
We know some of the answers already. There are immediate and significant savings in energy efficiency and conservation. Energy efficiency is not just low-hanging fruit; it is fruit lying on the ground. For example, we have the potential to make buildings 80 percent more efficient with investments that will pay for themselves in less than 15 years. Buildings consume 40 percent of the energy we use, and a transition to energy efficient buildings will cut our carbon emissions by one-third.
我们正在加速美国这座巨大的创新机器，这将是下一次美国大繁荣的基础。我们将大量投资有效利用太阳能、风能、核能的新方法，大量投资能够捕获和隔离电厂废气中的二氧化碳的方法。先进的生物燃料和电力汽车将使得我们不再那么依赖外国的石油。
