Johan Rockström at TEDCountdown@BloombergGreenFestival July 2024
Key Points
1 The planet is changing faster than we have expected. We are, despite years of raising the alarm, now seeing that the planet is actually in a situation where we underestimate the risks. Abrupt changes are occurring in a way that is way beyond the realistic expectations in science.
2 We’ve reached 1.2°C of global mean surface temperature rise, the warmest temperature on Earth over the past 100,000 years. We have just scratched on 1.5°C as an annual mean in 2023, but what worries us most is this. We are starting to see an acceleration of warming over the past 50 years. 0.18°C per decade from 1970 to 2010. But then from 2014 onwards it abruptly jumps up to 0.26 per decade, and if we follow this path, we will crash through 2°C within 20 years and hit 3°C by the year 2100, a disastrous outcome caused by us humans.
We’re seeing bigger and bigger invoices being sent by the Earth system onto societies across the entire world and droughts, floods, heat waves, disease factors, human reinforced storms scientifically attributed to human caused climate change. 40°C of life threatening heat across all continents occurring in 2020. 352°C hitting the over thousand who lost their lives at the Hajj pilgrimage in June in Mecca. Three times higher climate change risks now attributed to our cause of climate change. 2023 up to 12,000 deaths 200 billion U.S. dollars of cost Just in the US up to 100 billion U.S. dollars. This is seriously causing economic costs.
3. We have scientifically in the past show that this could cost a few percent of global GDP of the climate impacts caused by us. I can tell you that the latest scientific assessment is what you see on the screen here, an 18% loss of GDP by 2050. If we now follow the current path, this is equivalent to 38 trillion U.S. dollars of loss per year in 2050. It’s starting to hurt. Some human social cost and an economic cost. And this is happening at 1.2°C of row mean surface temperature rise and we’re following a path that takes us to 2.7°C in only 70 years and we’ve had a 10,000 year. Good. Where our civilizations have developed, where we’ve had an enormous privilege of a planet at 14°C + -, 0.5°C, That’s the Holocene since we left the last Ice Age. And if you look 3,000,000 years back, we never exceeded 2°C. That’s the warmest temperature on Earth during the entire Quaternary, the coldest point -5°C. I said. I call this the corridor of life. Is it surprising that we scientists are getting really, really nervous? But it’s more, it’s so much more than this.
4. Scientists are getting increasingly nervous – The first issue is buffering capacity, the 2nd is the risk of crossing tipping points and both are moving in the wrong direction. Buffering capacity is the Earth systems ability to dampen shocks or stress, like for example soaking up greenhouse gases and intact nature on land and in the ocean
5. Land absorbs 31% of the carbon dioxide from our greenhouse gas emissions. We have more and more scientific evidence across so much research that the borough forest and the Canada or the temperate mixed forest in Germany and Russia are starting to lose their carbon uptake capacity. Did you know that the latest science shows that been part of the Amazon rainforest, planet Earth’s richest Biome on terrestrial land, has already tipped over and is no longer carbon sink? It is today a common source. It’s no longer helping us. But as if that was not enough, what really worries us today is the ocean.
6. The ocean absorbs 90% of the heat caused by human induced climate change. This is well understood. But what really worries us is what you see here. This is the latest data on sea surface temperature across the ocean, which you see here is from 1980 until today. How gradually the ocean surface does get warmer and warmer. It’s actually warming all the way down to 2000 meters depth. Then suddenly in 2023, something happens. Temperatures just go completely off the charts. 0.4°C outside of the warmest temperature in previous years. What’s happening? We admittedly must be honest here. We do not know
7. The extraordinarily stable Holocene state and if we pushed ourselves outside, drifting away unstoppably towards the hothouse Earth where we get self amplified warming and losing life support on Earth. What could take us there? Well, we know it. It is if we cross tipping points. Big systems that could be an ice sheet, the overturning of heat in the North Atlantic, the coral reef systems, the Amazon rainforest are tipping elements systems. Push them too far and they will flip over from a desired state that helps us to a state that will self amplify in the wrong direction, going from cooling and dampening to self amplifying and warming. A rainforest tips over to a Savannah state now.
8. We have now mapped the 16 tipping element systems with a now scientifically catalog that regulate the climate system. These 16 are, you see the five and the Ground Zero on planet Earth and the Arctic are connected via cascades through the ocean, particularly via the Amos, the Atlantic overturning of heat in the ocean. All the way down to Antarctica
What this tells us is the following five of these sixteen are likely to cross the tipping points already at 1.5°C. The green light sheet, the West Antarctic Ice Sheet, abrupt thawing of permafrost, losing all tropical coral reef systems and collapse of the barren sea ice just into ice sheets.
9. Climate science estimates the risk of the Amazon rainforest tipping over irreversibly towards Savannah at three to five degrees of global mean surface temperature rise. A really high temperature, you know, unlikely even to be met over the next 70 years. But if we lose forest cover, the risk is that the system can tip already at 1.5 to 2°C if we lose more than 20 to 25% of forest cover. So that’s a very dangerous combination. Where are we today? We are at 1.2°C, global mean surface temperature rise and 17% of deforestation. We are very close to tipping point in the Amazon rainforest
10. On the pathway to stay under 1.5°C to avoid crossing tipping points, we need to operate to navigate within the global carbon budget that gives us a chance of holding 1.5. What? Claims for us is only 200 billion tons of carbon dioxide that we can continue knitting to have a 50% chance of holding 1.5. We emit today 40 billion tons of carbon dioxide per year, giving us five years at current rate of admission before we consume the budget. We are seriously running out of time and the pathway for a safe landing is also well studied and understood.
11. We must now be prepared for a very likely breaching of the 1.5°C planetary boundary on planet somewhere between 2030 and 2035 in five to 10 years time and then have at best a yea
12. The window is rapidly closing, but there is still some light in the window. We actually have evidence that we’ve reached a pivotal point, not only in terms of risk, but also in terms of opportunity to transform the world towards a safe and just future for humanity
We have the solutions for a secure, stable future for humanity. What are those transformations? Well, we know them. It’s a rapid transition away from fossil fuels. It is a transition towards circular business models. It is transitioning towards healthy diets from sustainable food systems. And it’s not only halting loss of nature, it’s also scaling the regeneration and restoration and marine system soils, forests and wetlands. We have solutions for all of these. Just take green energy, which today is cheaper than fossil fuel based energy. It’s our choice that we’re facing today
There is a light in the tunnel. And you may ask, what is it that makes me able to continue to be a realistic optimist in this situation? The most dire situation, I must admit, in my whole professional life. Well, actually, I promise this is an honest statement. There are so many positive items as well. The most important one in my mind is that we have ample evidence that citizens across the world, a majority of them care about nature and climate. They trust climate science, they’re concerned about climate change, and they want solutions. And the second key factor is that we have so much evidence today that the solutions are not only available, but if we implement them, we get a more healthy, stable, secure future with the jobs and the economies that can compete and provide livelihoods into the This means, dear friends, that solving the planetary crisis is not only necessary, it is possible, and we all win if we succeed.