My TED Talk is now live

We can live well and tackle our environmental problems at the same time. Let's do it.

The only thing more nerve-wracking than doing a TED Talk is watching that talk going live.

Back in April I gave a talk at TED Global. My talk is now live here.

In it, I present a vision for how we can continue to improve human wellbeing across the world while tackling our environmental problems at the same time.

For most of human history, these goals were often at-odds. More people meant more environmental damage and more resources. 

But, I don’t think that needs to be our future: we have the opportunity to do more with less. The emphasis here is on opportunity, not inevitability. There’s nothing inevitable about a better future: we have to create it.

It is a call to action: to move faster, and think bigger, so we can turn that opportunity into reality.

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Below, I’ve also provided a list of sources and elaborations on the main statements I make in the talk. I’ve done this for two reasons. First, it’s simply good practice to show where the data and research is coming from. Second, it allows me to provide some more details that I couldn’t fit into the talk. 

Delivering an overview of global sustainability in 12 minutes is hard. You can’t add the ten caveats and methodologies that you’d want to. At least not without (1) making it boring, and (2) driving the TED team crazy by going well over your time slot.

I suggest you watch the talk first. But if you have follow-up questions, feel free to dig into the sources and additional context below.

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Point 1

“56% think humanity is doomed; 75% think the future is frightening; 39% are hesitant to have children”

This data comes from a 2021 study by psychologist Caroline Hickman and colleagues, published in The Lancet: Climate anxiety in children and young people and their beliefs about government responses to climate change: a global survey.

It asked 10,000 young people – 1,000 across 10 different countries – a series of questions on their feelings about climate change. In addition to the statistics quoted above, respondents also felt strongly that government responses were not doing enough; were not taking climate concerns seriously; and were failing young people are future generations. 

These responses are completely understandable and expected. The potential impacts of climate change are severe, and those in power have not done enough to mitigate these risks.

I would have responded similarly to most questions, with the exception of humanity being doomed, and being hesitant to have children. As I wrote in a recent article, I continue to feel worried, anxious, and sad about our current trajectory.

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Point 2

“Half of children died before reaching puberty”

In the year 1800, estimated rates of youth mortality were around 48%. Around 43% of newborns died before the age of five. Then several percentage points more died before age 15.

As documented in this article by my colleague, Max Roser, this was true across the world, regardless of how rich countries were.

What about in earlier periods? There, the data is more scarce.

But researchers Anthony Volk and Jeremy Atkinson brought together a large number of studies of child mortality rates from across the world, spanning 2500 years. Max provides a nice visual summary in his article. The average mortality rate across 21 different historical societies was 48%. There were few exceptions to this.

Again, the data is even more scarce for hunter-gatherer societies. But the data from Volk and Atkinson, across 17 prehistoric and modern hunter-gatherers estimated an average mortality rate of 49%.

While there are large uncertainties about the demographics of our historical societies, the evidence strongly suggests that child mortality rates have been very high throughout our history.

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Point 3

“We’ve made a lot of progress on human wellbeing”

• Global child mortality rates have fallen to under 5%. The UN IGME estimates that 4% of newborns die before their 5th birthday. 4.3% die before the age of 15.
  
  This progress has been highly unequal, but child mortality rates have fallen significantly across every country in the world. See the change by region since 1990.
  

• Extreme poverty rates – those living on less than $2.15 per day – have fallen from around 79% in 1820 to 9% today.¹ Incomes are adjusted for inflation and cross-country price differences.
  
  The number of people living in extreme poverty has also decreased. At its peak in the 1970s, there were around 2 billion people living on less than $2.15 per day. Today, that figure is around 700 million.
  
  To be clear: $2.15 per day is an incredibly low poverty line. As I say later in the talk, this is far, far from an acceptable line.
  
  But poverty rates have also fallen at higher poverty lines.
  

• I reference positive trends in literacy (see here) and vaccination (see here). This data comes from the OECD, UNESCO, World Bank, and World Health Organization.

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Point 4

“This progress has come at the cost of the environment”

Links to the interactive charts, and sources for each chart are here:

• CO₂ emissions

• Energy use

• Coal burning

• Agricultural land

• Plastic production

• Meat production

“We kill billions of animals every year”

We kill over 80 billion land-based animals every year for meat. Data from the UN FAO is shown here. When fish, shrimps, and other animals are included, this is in the order of hundreds of billions to trillions.

“We use half of the world’s habitable land for agriculture”

This data comes from the UN FAO – I wrote about it here. Around 46% of the world’s ice- and desert-free land is used for grazing or croplands.²

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Point 5

“Per capita CO₂ emissions in the UK have halved”

The full series from 1750 is here. Emissions data comes from the Global Carbon Project, divided by population data from the UN.

In the 1970s, emissions peaked at around 11.8 tonnes per person. Today, they are around 5 tonnes per person, so they’ve more than halved.

Emissions are based on domestic production and do not include land use. Land use data is more uncertain, hence why I didn’t include it. But when we look at estimates with land use, the results are almost exactly the same.

Total emissions – not adjusted for population – are also around half of their peak in the early 1970s. Emissions fell from 660 million tonnes per year, to around 350 million tonnes today (chart).

“Per capita CO₂ emissions in the UK have also fallen when we adjust for offshoring”

The UK is a net importer of emissions. Its imports come to around 40% of its domestic total.

Consumption-based emissions are also calculated by the Global Carbon Project. I’ve made all of this data available here.

This data only goes back to 1990, but we can see that emissions in the UK have still fallen, even when we adjust for trade.

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Point 6

“A number of countries have decoupled GDP growth from CO₂ emissions”

The chart showing the change in GDP per capita, and CO₂ emissions is shown here. It includes trade-adjusted (consumption-based emissions).

The chart is interactive, so you can explore the data for any country.

I’ve also charted this for GDP and emissions not adjusted for population. It still holds true for a number of countries.

To be very clear: this decoupling is not happening fast enough. Far from it. And it is currently only rich countries that have achieved this.

We need to move much faster. I hope my talk contributes a tiny bit to pushing for this.

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Point 7

“Per capita CO₂ emissions have peaked globally”

The chart of this data is here. Based on emissions data from the Global Carbon Project, and UN population data, this reached a high point in the early 2010s. Note that there is no guarantee that emissions won’t rebound above this level: it’s up to us to make sure this is the peak once and for all.

This is still true when land use change emissions (which are more uncertain) are included.

“Global CO₂ emissions will peak soon”

I expect global emissions could peak in the next five years. Preliminary data confirms that emissions will rise again this year. And I also expect that they will rise again in 2024 (hopefully at a slower rate). But I think they could stop rising, somewhere in the period from 2025 to 2028.

The IEA now projects that all three fossil fuel sources – coal, oil and gas – will peak this decade. CO₂ emissions from these sources combined could peak before then.

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Point 8

“The death of coal across many countries”

I covered the rise and fall of coal in the UK here. Data is from the UK’s Governmental Statistics. See this from Simon Evans too.

Data on the share of electricity coming from coal is sourced from Ember Climate. I’ve charted this for the UK here, but the chart is interactive so you can add any country you like.

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Point 9

“Solar PV costs have plummeted”

The decline in solar PV costs is charted here. The chart has a log / linear button so you can switch between them.

This data is sourced from the work of Nemet (2009) (available here); Farmer and LaFond (2016) (available here) and IRENA (here).

If you’re interested, my colleague Max Roser looked at the rapid decline in solar and wind prices in an article: Why did renewables become so cheap so fast?

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Point 10

“Lithium-ion battery prices have plummeted”

This paper by MIT researchers, Ziegler and Trancik (2021) estimated that the cost of lithium-ion battery cells (not the full battery) fell by over 97% from 1970 to 2018.

Since 2018, BNEF data shows that costs have fallen further, resulting in a decline of around 98.5%. I covered this in a Substack post here.

If you use the cost of battery packs per kWh and multiply them by standard battery sizes, you can estimate the total cost. I did that in my article. The cost of EV batteries in 2022 was probably somewhere in the $5000 to $12,000 range, depending on size. Today, the batteries are probably even cheaper: prices continue to fall.

I did some back-of-the-envelope calculations to see what this cost would have been in the early 1970s. I estimated it was somewhere in the region of $400,000 to $900,000, depending on size. Large truck batteries could be more.

In the talk, I said that “a battery you’d find in a Tesla today would have cost a million dollars”. I think this is definitely an upper estimate, and actually wanted to say “between half a million and a million dollars”.

Note that lithium-ion batteries were not used for electric cars in the 1990s and early 2000s (the earliest EV prototypes were using other chemistries, such as lead-acid). My cost curve there is entirely hypothetical based on the size of EV batteries today. Lithium batteries were mostly used in consumer electronics. Their deployment and innovations through the 1990s drove dramatic cost declines.

By the 2000s, when they were starting to be used in initial EV prototypes for the mass market, they were already much, much cheaper. Batteries were smaller than the high-range models today too. By 2005, costs were probably below $50,000 in today’s prices (which is around 60% less in 2005 dollars). They were tens of thousands of dollars when they were first used.

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Point 11

“Electric car sales are taking off”

This data comes from the International Energy Agency (IEA).

I made an interactive slide deck for people to explore the data for a range of countries here.

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Point 12

“Global deforestation has peaked”

This data comes from the UN Food and Agriculture Organization. Every 5 years it publishes a global stocktake of forests and deforestation rates. This data is from its 2020 Global Forest Resources Assessment.

The chart showing the net change in forests is deforestation minus reforestation that has occurred.

Note that while global deforestation is reported to have fallen, levels of deforestation are still very high. For context, the loss of 150 million hectares in the first decade of the 2000s is around half the size of India. Even if this rate has been lower in the last decade, the world is losing large amounts of forests. Most of it is in the biodiverse tropics. We must strive to get this as close to zero as possible in the next 5 to 10 years.

I also think that, while reforestation is a great development, we cannot simply say that replanting a hectare of forest ‘offsets’ the loss of a hectare of primary forest. Stopping deforestation should be our first priority; regrowing forests should be second.

I wrote a long article on the history of deforestation, and how the UN FAO data compares to other sources in an article here.

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Point 13

“Crop yields in the US have grown six-fold”

This data is shown here, and comes from the US Department for Agriculture (USDA).

“The change in land use and corn production”

This chart is shown here. The data comes from the US Department for Agriculture (USDA), and the US Census Bureau.

The USDA also shows this in its summary charts of corn use here.

Note that when I say that the amount of land used for corn has not increased in over a century, I mean that land use for corn today is lower than it was a century ago, despite much, much higher levels of production.

It’s not the case that land use has not changed at all over that period. Land use decreased significantly in the first half of the 1900s, up until the 1960s. Since then, land use increased again (although not to the levels a century ago).

The main driver of this increase has been corn production for biofuels, which are mandated in the US. Nearly all of the growth in corn production since the 1990s has been for biofuels. I wrote about how inefficient this was for land use – and how the US could use it in a much better way – in a recent post. If the US was to prioritise corn for food production, it could use very small amounts of cropland given its high yields.

The core message of my talk is about the options that we now have, which our ancestors didn’t. It’s not inevitable that we make good choices – as evidenced by the US’s biofuels policy. But we do have the option to roll these back and go in a better direction.

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Point 13

“In many countries, solar and wind are now cheaper than coal”

The simplest metric to use here is the levelised cost of electricity (LCOE). Many sources report that solar and wind have the lowest LCOE of electricity technologies. Here is the International Energy Agency. Here is Lazard.

Lazard estimates that unsubsidised solar and onshore wind are the cheapest, without consideration of energy storage. Storage costs introduce large uncertainties: they are strongly dependent on the grid mix, demand curves, and type of storage. But even when storage is included, lower-to-mid range estimates are cheaper than coal, and competitive with combined cycle gas.

The opposite was true a decade ago – solar and wind were among the most expensive (see this article).

Note that I am aware that LCOE is an imperfect measure of electricity costs. A better measure is system costs, but these vary widely depending on the grid mix.

An additional important point is that the cost of solar and wind continue to fall (with temporary inflation hikes), while fossil fuels have virtually no learning curve, and are much more volatile due to fuel costs.

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Point 14

“Levels of air pollution in the US have fallen”

I show images of NOx pollution over the US. These images come from NASA.

Levels of air pollution have fallen dramatically in many rich countries. You can explore emissions of air pollutants across countries in a data explorer I created here.

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Point 15

The possibility, not inevitability of building a better future

I finish my talk by emphasising that, while there are positive signs of change, they are not close to being fast enough. We need to move much faster. My talk is a call to action to emphasise that change is possible – we see it in the data – but we need to work together to accelerate this progress. The status quo will not lead us to a good place.

What we have – that our ancestors didn’t – is choice. With choice comes responsibility. I encourage all of us to take that seriously and make choices that current and future generations will be thankful for.

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1. Note that the World Bank recently increased the international poverty line from $1.90 to $2.15. More info here: https://ourworldindata.org/from-1-90-to-2-15-a-day-the-updated-international-poverty-line

But this has little impact on the shares presented here.

2. This study by Ellis et al. (2010) estimated that 55% of Earth’s ice-free (not simply habitable land) is used for agriculture.

https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1466-8238.2010.00540.x