感谢邀请我。很高兴来到这里。巴黎是我在世界上最喜欢的地方之一。而且实际上，我第一次离开南非的旅行，去的就是巴黎，那是我小时候去的地方。好吧，我父母在我大约6岁时带我来的。所以从那以后我就一直很喜欢巴黎。因此，感谢邀请我。今天我要谈的只是从总体上说，应对气候危机需要做些什么。

而这就是，如果我们去做，我们可以采取哪些行动来加速摆脱化石燃料时代的转型？

所以我们今天所处的状况是。

让我们看看这是否值得，也许不值得。好的。

好。我们处在当今这个时代，这里有碳循环。如果你们中的一些人已经完全了解这些内容，请接受我的歉意，但我认为，其中一些事情也许并不像看上去那样显而易见。所以，有一定数量的碳在环境中循环。也就是说，它进入空气，被……吸收，然后被植物和动物吸收，再回到空气中。而这些，这些碳只是在地表循环。

这没有问题。而且它已经这样循环了数百万年、数亿年。发生变化的是，我们往其中加入了某种东西。所以这就是我所说的潘趣酒碗里的粪便。

所以，我们把所有这些额外的碳加入了碳循环，而最终结果是，是海洋的大气中的碳随着时间推移不断增加。其数量远远超过生态系统所能吸收的程度。

这其实非常简单。我们正在把数十亿吨被埋藏了数亿年、并不属于碳循环一部分的碳，从地下深处取出并加入碳循环。

结果是，大气和海洋中的，碳稳步增加，如果你在这张图表上看，这似乎并不算多，但放在历史背景下看，它实际上是这样的。

所以在大约1000万年里，碳的百万分率实际上一直在300这个水平上下波动。然后在过去几百年里，它开始垂直攀升。这就是问题的本质。正如你从这一增长速度中可以看出的那样，这非常反常，是一种极端严重的威胁。随之而来的还有温度上升，这也符合预期。

而这种温度上升，如果人们谈论2度或3度，就必须认识到气候实际上有多么敏感。对温度。重要的是要从绝对温度的角度看，而不是看相对于零点的摄氏度。我们需要说明相对于绝对零度的温度变化是多少。宇宙就是这样看待温度的，物理学也是这样看待温度的。

它是相对于绝对零度而言的。所以微小的变化会产生巨大的影响。纽约市被冰覆盖会是零下5度。纽约市被水淹没会是零上5度。但如果以相对于绝对零度的百分比来看，这仅仅是正负2%的变化。

所以气候的敏感性极其、极其高。我们把城市建在海岸线上，进一步放大了这种敏感性。而且大多数人都居住在离海洋非常近的地方。当然，有些国家地势非常低，在气候危机中会完全被水淹没。所以我们基本上把文明设计成了对气候变化超级敏感的形态。

需要认识到的重要一点是，我们终将退出化石燃料时代。所以我们退出化石燃料时代是不可避免的，因为到了某个时刻，我们根本就会耗尽可供开采和燃烧的碳。问题真正是，什么？我们何时退出这个时代？不是会不会，如果目标是尽快退出这个时代。

这意味着我们需要摆脱旧目标，也就是工业化前的目标，即从砍伐森林和杀死大量鲸鱼转变出去。

旧目标是从砍伐木材和捕杀鲸鱼转向化石燃料，在当时的背景下，这实际上是一件好事。但新目标是迈向可持续能源的未来。

我们希望使用水能、太阳能、风能、地热能之类的能源。在法国这种不易遭受自然灾害的地方，核能也是一个不错的选择。我们希望使用能够持续良好运行10亿年的能源。

那么，我们怎样才能加速这种从化石燃料向可持续时代的转型？

如果我们不这样做，会发生什么？

所以，如果我们等待，如果我们延迟改变，最好的情况，最好的情况也不过是推迟那场不可避免的可持续能源转型。这就是最好的情况。如果我们现在不采取行动，冒着重复的风险，从长远来看，我们将别无选择，只能转向可持续能源。这是同义反复。我们必须拥有可持续能源，否则另一种能源就会直接耗尽。所以，减缓转型能给我们带来的唯一结果，就是让它变慢。

这不会让它不发生，只会减缓它。然而，最坏的情况是，造成的流离失所和破坏会超过历史上所有战争的总和。

这些是最好的最坏情景。于是，大约3%的科学家相信最好的情况，大约97%的科学家相信最坏的情况。

这就是为什么我称它为有史以来最愚蠢的实验。你为什么要这么做？

转型之所以受到拖延或进展缓慢，是因为所有产生碳的活动都获得了一项隐性补贴。

在一个健康的市场中，假设你获得了€10的收益，同时给社会造成了€4的损害，那么利润就是€6。这显然说得通。在这种情况下，激励机制与美好未来是一致的。

如今并非如此。但如果让激励机制保持一致，那么推动我们迈向美好未来、迈向可持续能源未来的驱动力就会非常强大。

在一个不健康的市场中，你获得€10的收益，也造成了€4的损害，但这€4没有被征税。你有一个未被征税的负外部性。这基本上就是经济学101。所以你基本上获得了不合理的利润，并产生了从事碳排放活动的驱动力。因为这个，这个社会成本并没有得到支付。

最终结果是每年有35吉吨碳进入大气。

所以这就类似于不支付垃圾收集费用。而且我们不应该说，就垃圾而言，要建立一个零垃圾社会。建立零垃圾社会非常困难，但重要的是人们要为垃圾收集付费。

所以，我们需要摆脱未被征税的负外部性，它实际上是一项规模巨大的隐性碳补贴，据国际货币基金组织称，每年为$5.3万亿。每年我们都需要摆脱这一点，并征收碳税。

但碳生产商正在竭力反对这一点，他们使用的策略与卷烟业或烟草业多年来使用的策略非常相似。

他们会采取拥有……的做法。尽管压倒性的科学共识认为吸烟对你有害，他们还是会找出少数持反对意见的科学家，然后说，看，科学家们存在分歧。所以他们基本上就是这样试图欺骗公众，让公众认为吸烟并没有那么糟糕。

解决办法显然是取消补贴。

所以这意味着我们需要征收碳税，而为了让它不成为一个左派或右派议题，我们或许应该实行收入中性的碳税。这将意味着提高对碳的税收，同时降低其他方面的税收。比如可以降低销售税或增值税，同时提高碳税，从而只有那些大量使用碳的人才需要缴纳更多税款。

而且，我是说，为了给行业留出反应时间，可以采用分阶段实施的方法，也许要过5年碳税才会变得非常高。这意味着只有今天不采取行动的公司才会在5年后受到损失。但政府需要在这方面发出明确的信息，因为根本问题在于，今天的规则鼓励人们制造碳，而这太疯狂了。

而无论你激励什么，它都会发生。这就是为什么到目前为止我们看到的成效非常小。

而我们采取什么行动，将把碳数值推向极端水平或温和水平。

我认为，温度升高2°C几乎是必然会发生的。问题在于升幅是否会远远超过这一数值，而不是会不会升高2度。

所以接下来的问题是，那么你能做什么？我会说，只要有机会，就去和你们的政治人物交谈，请他们制定碳税。我们必须解决未被定价的外部性问题，和你的朋友谈谈这件事，并反击碳行业的宣传。

这就是我要传达的基本信息，我很乐意回答问题。

Thank you for having me. It's great to be here. Paris is one of my favorite places in the world. And it's actually on the first trip that I went out of South Africa. Paris, that was where I went when I was a little kid. Well, my parents brought me when I was like 6 years old. So I've loved Paris ever since. So thank you for having me. What I'm going to talk about today is just in general terms, what is needed to address the climate crisis.

And this is the thing that if we do, what actions can we take that will accelerate the transition out of the fossil fuel era?

So where we are today is.

Let's see if this is worth it, maybe not. Ok.

All right. We have the present era where we have the carbon cycle. My apologies if some of you already know all about this, but I think some of these things are maybe not as obvious as they may seem. So there's a certain amount of carbon that is circulating through the environment. So it's going into the air, being absorbed by, and then getting absorbed by plants and animals and then going back into the air. And this, this carbon is just circulating on the surface.

And this is fine. And it's been doing that for millions, hundreds of millions of years. The thing that's changed is that we've added something to the mix. So this is what I would call the turd in the punch bowl.

So we added all this extra carbon to the carbon cycle, and the net result is, is that the carbon in the ocean's atmosphere is growing over time. It's much more than can be absorbed by the ecosystem.

It's really quite simple. We're taking billions of tons of carbon that's been buried for hundreds of millions of years and is not part of the carbon cycle, taking from deep underground and adding it to the carbon cycle.

The result is that a steady increase in the, the carbon in the atmosphere and in the oceans, which doesn't look like much if you look at it on this chart, but when looked at in the context of history, it actually looks like this.

So the carbon parts per million has really been bouncing around the 300 level for around 10 million years. And then the last few hundred years, it went into a vertical climb. This is the essence of the problem. This is very unusual and a very extreme threat, as you can see from this rate of growth. Then this is accompanied by a temperature increase, as one would expect.

And this temperature increase, if people talk about 2 degrees or 3 degrees, it's important to appreciate just how sensitive the climate actually is. To temperature. And it's important to look at it in terms of absolute temperature, not in degrees Celsius relative to zero. We need to say what is the temperature change relative to absolute zero. That's how the universe thinks about temperature, it's how physics thinks about temperature.

It's relative to absolute zero. So for small changes result in huge effects. So New York City under ice would be minus 5 degrees. New York City underwater would be plus 5 degrees. But looked at as a percentage relative to absolute zero, it's only a plus minus 2% change.

So the sensitivity of the climate is extremely, extremely high. We've amplified this sensitivity by building our cities right on the coastline. And most people live very close to the ocean. Some countries of course, that are very low lying and would be completely underwater in a climate crisis. So we've essentially designed civilization to be super sensitive to climate change.

And the important thing to appreciate is that we are going to exit the fossil fuels era. So it is inevitable that we will exit the fossil fuel era because at a certain point we will simply run out of carbon to mine and burn. The question is really what? When do we exit the era? Not if the goal is to exit the era as quickly as possible.

That means we need to move from the old goal with the pre industrial goal which was to move from chopping down forests and killing lots of whales.

The old goal was to move from chopping wood and killing whales to fossil fuels, which actually in that context was a good thing. But the new goal is to move to a sustainable energy future.

And we want to use things like hydro, solar, wind, geothermal. Nuclear is also a good option in places like France which aren't subject to natural disasters. And we want to use energy sources that will be good for a billion years.

So how do we accelerate this transition away from fossil fuels to a sustainable era?

And what happens if we don't?

So if we wait and if we delay the change, the best case, the best case is simply delaying that inevitable transition to sustainable energy. So this is the best case. If we don't take action now, at the risk of being repetitive, there's going to be no choice in the long term to move to sustainable energy. It's tautological. We have to have sustainable energy or we'll simply run out of the other one. So the only thing we gain by slowing down the transition is just slowing it down.

It doesn't make it not occur, it just slows it down. The worst case, however, is more displacement and destruction than all the wars in history combined.

These are the best worst case scenarios. So then we have about 3% of scientists that believe in the best case, about 97% that believe in the worst case.

This is why I call it the dumbest experiment in history ever. Why would you do this?

The reason that the transition is delayed or is happening slowly is because there is a hidden subsidy on all carbon producing activity.

In a healthy market, if you have, say, €10 of benefit and €4 of harm to society, the profit would be €6. This sort of makes obvious sense. This is where the incentives are aligned with a good future.

This is not the case today. But if you have the incentives aligned, then the forcing function towards a good future, towards a sustainable energy future, will be powerful.

In an unhealthy market, you have your €10 of benefit, you have your €4, but the €4 isn't taxed. You have an untaxed negative externality. This is basically economics 101. So you have basically unreasonable profit and a forcing function to do carbon emitting activity. Because this, this cost to society is not being paid.

The Net result is 35 gigatons of carbon per year into the atmosphere.

So this is analogous to not paying for garbage collection. And it's not as though we should say, in the case of garbage, have a garbage free society. It's very difficult to have a garbage free society, but it's just important that people pay for the garbage collection.

So we need to go from having untaxed negative externality, which is effectively a hidden carbon subsidy of enormous size, $5.3 trillion a year, according to the IMF. Every year we need to move away from this and have a carbon tax.

But this is being fought quite hard by the carbon producers and they're using tactics that are very similar to what the cigarette industry or tobacco industry used for many years.

They would take the approach of having. Even though the overwhelming scientific consensus was that smoking cigarettes was bad for you, they would find a few scientists that would disagree and then they would say, look, scientists disagree. So that's essentially how they would try to trick the public into thinking that smoking is not that bad.

The solution obviously is to remove the subsidy.

So that means we need to have a carbon tax and to make it sort of something which is neither a left nor a right issue, we should make it probably a revenue neutral carbon tax. So this would be a case of increasing taxes on carbon, but then reducing taxes in other places. So maybe there would be a reduction in sales tax or VAT and an increase in carbon tax so that only those using high levels of carbon would pay an increased tax.

And moreover this, I mean in order to give industry time to react, this could be a phased in approach that maybe it takes five years before the carbon taxes are very high. So that means that only companies that don't take action today will suffer in five years. But there needs to be a clear message from government in this regard because the fundamental problem is the rules today incent people to create carbon and this is madness.

And whatever you incent will happen. That's why we're seeing very little effect thus far.

And depending upon what action we take, will drive the carbon number to either extreme or moderate levels.

I think it's pretty much a given that the 2°C increase will occur. The question is whether it's going to be much more than that, not if there will be a 2 degree increase.

So then the question is, so what can you do? I would say whenever you have the opportunity, talk to your politicians, ask them to enact a carbon tax. We have to fix the unpriced externality, talk to your friends about it and fight the propaganda from the carbon industry.

So that's the basic message I have and I'm happy to take questions.