What the news won't tell you about climate change | Hannah Ritchie, PhD

• I think many people today feel doomed about the state of the planet. They see climate change and they think, 'These problems are insurmountable and we just won't be able to solve them.'

Now, I've previously been in the same position. I just couldn't see how we would possibly be able to tackle these problems. Actually, by stepping back to look at the data and looking at how the world has changed over centuries, you can actually find examples of really big environmental problems that we've already solved. So it's not like humans aren't capable of solving problems; we are, and you can only see that when you switch off the news and step back to look at the data. You can see that while we face really, really big urgent problems, we are developing the solutions and these challenges are solvable.

My name is Hannah Ritchie. I'm a researcher at the University of Oxford, and I'm deputy editor of Our World in Data. The main driver of climate change today are human emissions of greenhouse gases. Now, these come from a range of sources. I think there's four key areas that we need to target in order to solve climate change: energy, transport, food, and construction.

So what's really key to transforming our energy system is that we need to move away from fossil fuels to low carbon sources of energy, such as solar, wind, hydropower, geothermal, and nuclear. But many people are quite rightly concerned about the potential implications for land use by moving to renewables. They picture fields filled and full of solar panels and all of our landscapes transformed into wind farms. Actually, when you run the numbers, they tell a slightly different story.

When we look at how much solar we would need to meet demand for the world's electricity today, we could actually produce that on less than 1% of the world's land. For wind, you're probably talking 5%, but the direct impact of actually putting a wind turbine in the ground is very, very small—much, much less than 1% of the world's land. And you can actually use the land between wind turbines for uses such as farming.

Now, if you wanted to spare as much of the world's land as possible, your best option would be nuclear. You could feasibly power the world on less than 0.1% of the world's land. And many people are concerned that we might not have enough lithium, copper, and a range of other minerals to decarbonize our electricity grids. But actually, when you look at the data, it's very clear that we do. I think what's also key to highlight there is that these numbers are never static. Our known reserves tend to increase over time, not decrease.

I think the other concern that people have is the sheer environmental impact of all the stuff that we'll have to mine out of the Earth, and we will need to mine a lot. We probably need to mine ten to hundreds of millions of tons of different minerals to build all of the infrastructure that we need. Now, at first glance, that sounds really alarming—ten to hundreds of millions of tons. But contrast that with what we're currently doing with fossil fuels, where we're digging out 15 billion tons every single year.

What's really, really key about this transition to low carbon sources of energy is that the alternatives to fossil fuels need to be cost competitive. We will not make progress on this problem if solar, wind, or nuclear are more expensive than coal or gas. But there's some good news here. Solar and wind were among the most expensive energy sources that we had. Over the last decade or so, we've seen really rapid reductions in their costs such that they're now cost-competitive or even cheaper than coal or gas.

That means that making this transition is not just about economic gains in the long term; when we factor in the impacts of climate change, it's already cost-competitive and economic to make this transition today. So, around a fifth of our CO2 emissions come from transport. Now, most of that comes from cars and trucks on the roads, and the rest comes from rail, shipping, and aviation.

I think the most obvious way to reduce our transport emissions is just to drive less—to walk, or to cycle, or to use public transport. But I think we should also acknowledge that we won't be able to get rid of cars completely, but we can start to decarbonize cars as well. You know, the question I always get is: So, in the U.K. for example, the electric car will initially have higher embedded emissions than a petrol or diesel car. That's because it does take more energy to produce the battery.

But once you start driving the car, this very, very quickly pays off. After just two years of driving, the average driver will have paid off the carbon debt of manufacturing the car in the first place. And from then on, you just get really rapid reductions in the CO2 emissions compared to a petrol or diesel car. So, over the lifetime of the car, you're probably talking about a reduction of around half to two-thirds compared to a petrol or diesel car. But what's really key about this is that your electric car will get cleaner and cleaner over time.

That's 'cause we'll also be decarbonizing our electricity systems as we move over the next decade. Now, many people might think that this transition is impossible because we just keep seeing more and more and more petrol cars on the road. But actually, the world has already passed the peak of global sales of petrol and diesel cars. They peaked in 2018 and they are now falling. All of the growth in the car sector is now coming from electric vehicles.

So, around a quarter of our global emissions come from food, and that comes from various sources. One of the key ones is land use change. We often imagine that our impact on land use in the world is very much about urban landscapes and roads and infrastructure—but this actually makes up less than 1% of the world's land use. In contrast, our biggest footprint in terms of land use is farming. We use almost half of the world's habitable land for farming, and here some of these key emissions are actually not carbon dioxide, but other greenhouse gases such as methane and nitrous oxide.

There are probably three key ways that we can reduce emissions from foods: One is to make our food systems much more productive, to get much higher yields per hectare of land. I think the second key one there is dietary change. I mean, look at the carbon footprint of different foods. What we tend to see is that meat and dairy has a much higher carbon footprint than plant-based foods. I think the final one is just simply wasting less food. The problem with food waste is not necessarily the emissions when it goes to landfill; it's all of the emissions that come from producing the foods that then isn't going actually into people's mouths at the end of the chain.

The final source of emissions is construction and manufacturing. There's a couple of components to where these emissions come from: One is just using energy to produce the stuff, and we know how to decarbonize that. But for some key materials, they're more direct emissions. Take the example of cement: So how we produce cement is that we take limestone, we turn it up at very, very high temperatures, but as a byproduct, we also produce CO2.

So, what we really need to do is get rid of that CO2 byproduct from this process. Now, there are a couple of key ways that we can reduce emissions from cement. One is actually to just use less cement. Now, that doesn't necessarily mean using less building materials, but we can use a lower grade or a lower composition of cement in our final product that we then use to produce buildings.

I think the second key one that we can do is we can capture that carbon dioxide at the end of the process. We can then either actually put it back into the cement, where it can potentially make it stronger, or we can capture it and store it safely underground so it doesn't escape into the atmosphere. The final way, which some companies are innovating on, is not using limestone as the source rock in the first place. They're experimenting with sources such as calcium silicate, which will give you the same cement, the same product that we need. Because there's no carbon in there, you won't get the CO2 at the end of the chain.

So, we have a couple of key solutions which might come online in the next decade in order to decarbonize cement. Although we might be able to do this feasibly from a technical perspective, what's really, really key is that we drive the cost down such that they're no more expensive than what we already have. So, these are four key areas that we need to target in order to solve climate change.

I like to frame myself as an 'urgent optimist.' Now, this is different from a 'complacent optimist' or a 'stupid optimist,' which is someone who just assumes that the future will be better than it is today. No, it won't. It will only be better if we make it better. If you look at the evolution of human history, human progress was often very much in conflict with environmental impact. The more that humans progressed, the more the environment degraded.

I think we're in this really unique position where I think these two things are no longer in conflict because we have technologies that decouple our human well-being from our environmental impact. We have institutions that can put policies around this to drive this further. And we have more intelligent, educated humans than ever who are really, really serious about working on these problems. It's not inevitable that we do this, but I think it's important that we can see that there's an opportunity there and it's really up for us to grab it and to make it happen.

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