The air we breathe has changed. The mix of gases is shifting, with more and more greenhouse gases like carbon dioxide. And this shift is happening faster each year. In fact, concentrations of CO2 have reached levels never before breathed by humans, since Homo sapiens evolved. In just a few hundred years, eons of fossilized sunshine have been burned as coal, oil and gas. The exhaust has transformed the entire atmosphere and ocean. It’s like a pollution blanket, and the result we know as climate change.
我们所呼吸的空气变了。 随着二氧化碳等温室气体的增加, 大气的成分正在改变。 而这个变化正在逐年加快。 实际上,自智人演化以来, 二氧化碳的浓度已达到 人类有史以来从未呼吸过的水平。 在短短几百年的时间里, 数亿万年的化石以煤、石油 和天然气的形质被燃烧。 废气的排放改变了整个大气层和海洋, 造成铺天盖地的环境污染, 引发了我们所知的气候变化。
So how much more of that fossilized sunshine can we burn before further destabilizing the Earth’s systems? Not much. Think of it as a carbon budget. We are currently adding 55 billion metric tons of greenhouse gases to the atmosphere every year. This is the Gigaton Challenge. By some estimates, at that pace, we will have burned through the remaining budget by 2030. So to give us some room to breathe, the world must reduce greenhouse gas pollution by more than seven percent each year, every year of this decade ... starting now.
在地球的生态系统被愈加破坏之前 我们到底还能燃烧多少化石? 不多了。 就把它想成是碳预算。 我们目前每年排放 550亿吨温室气体。 这就是“千兆吨挑战”。 根据一些预测,在这种速度下, 我们截至2030年将耗尽剩余的预算。 因此,为了给我们呼吸的空间, 全球必须在未来的十年内, 每年减少高于7%的 温室气体排放量… 从现在开始。
There are a number of ways to do that. Let’s start by looking at the greenhouse gases themselves. CO2 makes up nearly 75 percent of the pollution emitted each year. There’s also nitrous oxide, known as laughing gas, but it's no laughing matter, seeping out of farm fields and elsewhere and making up six percent of the problem. And then there’s methane, which you may also know of as natural gas. It’s 17 percent of the total. There are other greenhouse gases, but these three make up the bulk of the climate challenge. All must be reduced -- and fast.
我们可通过一些途径来实现其目标。 让我们从了解温室气体开始。 二氧化碳每年占将近75%的废气排放量。 一氧化二氮也是其中一种废气, 它也被称为“笑气”, 但这并不好笑, 因为它正从农场或其他地方泄露, 并占问题的6%。 接下来是甲烷, 这也是众所周知的“天然气”。 它占总排放量的17%。 当然还有其他温室气体, 但这三个占了气候挑战的绝大部分。 所有废气排放都必须 尽快减少。
Methane is better at trapping the Sun’s heat, which means cutting methane pollution is a necessary and fast-acting stimulus for our carbon budget. If methane emissions from agriculture and the oil and gas industry can be eliminated in this decade, we might be able to stave off catastrophes like the loss of the Arctic sea ice and glaciers all around the world.
甲烷比较会捕捉太阳的热气, 因此减少甲烷污染 对整个碳排放预算来说 是必要和速效的强心剂。 如果我们能在未来的 十年内消除来自农业 和石油与天然气产业的甲烷排放, 我们或许能避免诸多浩劫, 例如北极海冰和全球冰川的融化。
CO2 has a longer life. Once it is added to the atmosphere, it can stay up there for hundreds of years, if not longer. CO2 emissions must be cut in half by 2030, and then reduced even further by 2040, to put the world on a path of adding no CO2 to the air by 2050. And that means transforming the modern world as quickly as possible.
二氧化碳的寿命较长。 当它被排放到大气中时, 它可以在那里待上几百年, 甚至更久。 截至2030年,二氧化碳的 排放量必须减半, 并且到了2040年进一步减少, 才能在2050年前 实现全球净零碳排放。 这意味着我们要尽快改变现代社会。
There are several ways to break down the sources of greenhouse gas emissions. Here we’re using the public Climate Watch data. Start with energy. The majority of modern energy comes from fossil fuels, which makes the energy sector 76 percent of the climate challenge, including the fuels used for transportation, industrial processes and agricultural production. The shift to clean energy must be accelerated by an order of magnitude if we want any chance to restrain global warming to 1.5 degrees Celsius. And we’ll need more ways to store this clean electricity, whether that’s putting it in the chemical bonds of a battery or into a molecule of hydrogen. Batteries and clean hydrogen are also going to play a key role in cleaning up transportation, which accounts for 17 percent of climate-changing pollution, including the use of energy to move people and goods around: eight percent from cars; five percent from trucks and other heavy-duty vehicles; and four percent from shipping and aviation. With abundant clean electricity, the world can win the race to electrify cars and create cleaner alternative fuels for trucks, ships, and even one day, airplanes.
我们可通过几种方法来 解析温室气体排放的源头。 在这里,我们使用的是 公共气候观测数据。 从能源开始。 现代能源大部分来自化石燃料, 因此能源市场构成了气候挑战的76%, 其中包括用在运输、 工业程序和农业生产的燃料。 若我们想将全球暖化限制在 1.5摄氏度以内, 我们转向清洁能源的步伐 就须加快一个数量级。 而且我们需采用更多方式 来储存清洁能源, 不管是将其放进电池的化学键里 还是氢气的分子里。 电池和清洁氢气将在 交通领域的绿化中 扮演重要的角色, 而交通占了导致气候变化的污染的17%, 这当中包括使用能源来运输人和物: 8%来自汽车; 5%来自卡车和其他重型车辆; 4%则来自航运和航空。 有了大量的清洁能源后, 世界就可成功将汽车电动化 和为卡车、轮船、乃至飞机创造 更清洁的燃料。
Then there are our lifestyles and the materials that make them possible. That’s everything from the cement and steel that go into buildings to the plastic fibers in fashion. All told, these materials account for six percent of our emissions -- on top of the energy emissions required to produce them. And we’ll need new and clean ways to make them or replace them.
但若想战胜气候挑战,我们也得 改变生活方式和所使用的物质。 这包括用在建设方面的钢筋水泥 和时装里的塑料纤维。 这些材料占总排放量的6%, 当中不包括生产过程中的能源排放。 而我们需找到新颖、清洁的方式 来制作或代替这些材料。
Farming and animal raising also have to change as agriculture accounts for 12 percent of greenhouse gas pollution. That means everything from how and what people eat to how and what cows, chickens and pigs eat. It also means finding ways for farm fields to go from sources of greenhouse gas to places where greenhouse gases get buried. Agriculture is also the biggest direct impact people have on the plants, animals, microbes and fungi that share this planet with us. To truly solve the climate challenge, the wild world will have to be protected and restored to allow all of life’s myriad forms to flourish. A halt in cutting down forests, burning peatlands and converting coastal wetlands could prevent the release of nearly five billion metric tons of greenhouse gases each year. Restoring nearly 200 million hectares of degraded forestland, peatland and wetlands could also absorb almost another four billion metric tons. Perhaps even more importantly, the ocean has vast potential to help reduce greenhouse gases ... if we protect it.
农作和牧业也须改变 因为农业占温室气体排放的12%。 改变农业意味着改变人们和牲畜 进食的方式和食用的食物。 改变农业也表示找到如何将农地 从排放温室气体的地方 转为埋置温室气体的地方。 农业也是人类对动植物、 微生物和真菌等 地球原住民造成的最大、 最直接的影响。 想真正解决气候问题, 我们就须保护和恢复大自然 以让所有生物都能蓬勃生长。 停止森林砍伐 和泥炭地的燃烧 以及转换沿海湿地的用途 将可避免人类达到 约50亿公吨的总年度温室气体排放量。 恢复近2亿公顷的遭破坏的森林、 泥炭地和湿地 也可吸收大约40亿公吨的温室气体。 或许更重要的是, 海洋在减少温室气体这方面 具备广大潜力, 但前提是我们要保护它。
Finally, there are technologies being developed to draw down CO2 from the atmosphere because we have already emitted too much. But very few of these machine forests have been deployed and they are too expensive to scale up faster right now.
最后,由于我们已排放太多温室气体, 我们正在开发新技术 以从大气层中去除二氧化碳。 但目前,少数“机械树林”已被动用 而且想在现刻扩大其规模也太昂贵。
This is the climate challenge we face: going from adding 55 billion metric tons of greenhouse gases to the air each year, to adding zero by 2050, at the latest. The countdown begins now.
这是我们所面临的气候挑战: 从每年排放550亿公吨的温室气体 到最晚在2050年前实现 净零排放。 时间从现在开始倒数。
(Music)
(音乐)
[Countdown]
【倒数】