Tipping Points

What are tipping points, and why should we care?

A climate “tipping point” refers to a threshold beyond which small changes to global temperatures can have big, irreversible effects.

For example, you’ve probably heard that scientists are concerned about the melting of the huge ice sheet that covers Greenland. If the world isn’t able to rein in global warming, the melting will eventually become self-sustaining and irreversible, researchers have determined.

That’s a tipping point.

If this threshold is crossed, the melting could raise sea levels by as much as 23 feet over the course of several centuries, swamping coastal cities around the world.

The idea of climate tipping points has been around for decades, although there is debate about how many there are and at what temperatures they will be reached. The big ones, however, are generally accepted to include the melting of the ice sheets in Antarctica and Greenland; the thawing of Arctic permafrost; the collapse of a major ocean circulation system; and the shrinking of the Amazon rainforest.

Recent research suggests that some of these changes may start to occur once global warming reaches between 1.5 and 2 degrees Celsius (2.7 and 3.6 degrees Fahrenheit) above preindustrial average temperatures. And the world is already 1.2 degrees Celsius warmer than it was in the 19th century. — Henry Fountain

Timothy Lenton

Timothy Lenton is a professor of climate change and Earth system science at the University of Exeter. He started working on tipping points in the 1990s, making him one of the first scientists in the world to study this form of planetary risk. In an upcoming book, Positive Tipping Points: How to Fix the Climate Crisis, he argues the Earth has entered an “unstable period” but humanity can still prevail if we can trigger positive social and economic tipping points to reverse the damage that has already been done. On 30 June, he will host a global conference on tipping points.

How do you define a tipping point?
A tipping point is where change becomes self-propelling within a system, meaning it will shift from one state to another. That can happen because the balance of feedback in the system switches from damping feedback to amplifying feedback. The result can look very rapid and irreversible.

How has our understanding of these risks changed?
We first published a map of climate tipping elements in 2008, Since then, we have added much more than we have subtracted from that map. And, unfortunately, in the intervening 17 years, the evidence suggests we’re much closer to some of these tipping points than we thought.

Which tipping points might we have passed?
Things are undoubtedly happening faster than anticipated. The tipping points of greatest concern include the West Antarctic ice sheet, where the loss of a significant chunk of the ice sheet is self-propelling, which could raise the world’s sea levels by about 1.2 metres. There is also the Greenland ice sheet, which is losing mass at an accelerating rate. Then we have the permafrost, parts of which are already passing localised tipping points – and that’s adding methane and carbon dioxide to the atmosphere. Then there’s the unprecedented bleaching and dieback of coral reefs, which hundreds of millions of people depend on for their livelihoods.

And which are close?
There’s a tipping point in the circulation of the north Atlantic Ocean, when deep water stops forming in the middle of the subpolar gyre south-west of Greenland. That system seems quite volatile, and a tipping point there is like a small version of a bigger tipping point of the Atlantic meridional overturning circulation (Amoc), which studies suggest is at much greater risk than we thought even a few years ago. That in turn could trigger monsoon tipping points in west Africa and India. I’d also note the risk of tipping Amazon rainforest dieback from a mixture of climate change and direct human disruption. Unfortunately, I could reel off quite a few more.

How accurate are the predictions?
If anything, we have underestimated the risks. When we did our first assessment in 2008, we thought Greenland was close to a big tipping point. We haven’t changed that judgment, but we thought West Antarctica would need at least 3C of warming [above pre-industrial levels]. Unfortunately, everything that’s been observed since suggests we were way too optimistic. As a rule, the more we learn, the closer we think the tipping points are – and meanwhile we’ve been warming the planet up. It’s like running faster into a sea that is rising to drown us.

Why has it taken so long for the world to talk about these catastrophic threats?
In the climate science community, we have tended to concentrate on assessing what’s the most likely thing to happen, but the more important question is: what’s the worst thing that could happen? That’s the difference between a scientific assessment and a risk assessment. I would argue we’ve not been treating climate change as a risk assessment.

That is also because a lot of well-funded entities have been systematically undermining the knowledge consensus on climate change, which has forced the scientific community to defend what’s in effect 19th-century physics. That hasn’t put us in a great position to emphasise tipping point risks, which inherently have more uncertainty around them.

Why do we need to talk about them now?
Because tipping point risks are real and potentially existential. If we have a tipping point in the Atlantic Ocean – the so-called Amoc – we could lose more than half the area for growing staple crops worldwide. It would cause water security crises and severely disrupt the monsoons in west Africa and India, which would affect billions of people.

We have to level up to those risks, better understand them and how close they are, and what things we can do in response. Even if we can’t stop the events happening, we can do things that reduce the vulnerability of people exposed to the risks. That is why we are drawing attention to tipping points. This is not as a council of despair; on the contrary, it is more like a council of practicality. In terms of the upfront costs to decarbonise the global economy, it is a great investment for the return you get, which is lowering the risk of otherwise catastrophic outcomes.

It would help if the IPCC [the United Nations Intergovernmental Panel on Climate Change] took a more in-depth look at tipping points. A large number of countries wanted to see an IPCC special report on tipping points in this assessment cycle, but the IPCC said no. Instead there’s due to be a chapter in the next assessment report.

Is there an alternative?
Yes. I and more than 200 other researchers have published a global tipping points report, and we’re writing another one for Cop30, [the UN climate change summit which takes place in Brazil, in November]. We felt the risk was important to communicate and this is a timely moment. So we are trying to fill in the assessment gap in an accessible way. People are crying out for that.

I understand the global tipping points conference will also look at positive tipping points in technology, economics and politics?
Yes. [There are some] more optimistic scenarios; the impacts of wind power and photovoltaic innovation, or the knock-on effects of campaigning by Greta Thunberg and others. There are also policy feedbacks that could create a change in the landscape in a good way, where you start a policy path towards the renewable energy revolution that’s very hard to reverse. That is arguably what the architects of the German feed-in tariffs for renewables managed to do. They made it hard for the doubters to change course even after a change of government.

Has renewable energy reached a positive tipping point?
Yes, our analysis suggests that solar photovoltaic power is now in a phase of self-propelling global uptake with exponential growth of installed generating capacity, doubling every two years or less. Factoring in the cost of battery storage, solar is already the cheapest source of new power in most of the world, and for every doubling of installed capacity its price drops by nearly a quarter. This is rapidly making solar power the cheapest source of electricity ever, which brings many benefits, including access to electricity for the roughly 700 million people who don’t currently have it.

And electric vehicles?
Yes, the price of batteries plummeted nearly tenfold in a decade as the range you can get from a given mass of battery increased by nearly a factor of three. This has brought China and several European markets to the tipping point where adoption of EVs is self-propelling: the more EVs that get bought, the better and the cheaper they get, encouraging further adoption. The US is lagging behind, but the global south is starting to reap the benefits of electrifying mobility, as it is much cheaper to run an electric rickshaw in India or an electric motorbike taxi in east Africa than their fossil-fuelled equivalents.

Any other examples of potential positive tipping points?
I’m working on regenerative nature. We already see cases where degraded ecosystems have been tipped back into a better state – for example, when wolves were reintroduced to Yellowstone National Park and started preying on elk, it triggered abrupt vegetation recovery, or when sea otters returned to north Pacific coastal ecosystems and started feasting on sea urchins it tipped the recovery of kelp forests. We also see social tipping points that are nature-positive, where community conservation initiatives, like locally managed marine protected areas, spread rapidly and widely among and across societies.

Can you explain cascading feedbacks?
In all complex systems – such as the climate and the economy – if you can tip one thing, it can have consequences for other bits of the system. If you tip one part of the system it can make tipping another part of the system more likely. For example, if you’ve suffered a medical shock it can have knock-on effects on other parts of the body. In the climate, these causal connections can be quite significant and strong. In Earth’s history, when there were tipping points in the overturning circulation of the Atlantic Ocean, that tipped major shifts in the tropical monsoons of west Africa and India.

In the economy, a cascade can be more positive. For example, an investment in renewable energy can bring forward a tipping point in other sectors. It basically means renewables are making electricity cheaper than it has ever been, and that incentivises electrifying mobility, like cars and trucks and buses, or electrifying heating in homes. At the same time, batteries get cheaper because of economies of scale, which then helps to balance renewable electricity supply and demand. So feedbacks between sectors of the economy can create tipping points that reinforce each other. We’ve recently mapped out a bunch of positive tipping cascades that could help accelerate change to zero greenhouse gas emissions.

What should the world do at Cop30 in Belém to address tipping points?
We need policymakers to implement policies that bring forward the positive tipping points we need to stop greenhouse gas emissions and prevent the bad climate tipping points. If the EU and China were to coordinate, it could be enough to shift the balance towards clean green alternatives. Even with Trump in the United States, the beauty of tipping points is you don’t need everybody, you typically only need a fifth to tip to the new alternative and then you get to a situation where everybody else is compelled to follow.

Positive Tipping Points

Positive tipping points in the context of climate change refer to shifts or changes that can significantly accelerate progress towards sustainability and decarbonization. These are crucial as they can potentially catalyze large-scale social and technological transformations necessary to address climate change efficiently and quickly.

1. **Definition**: In environmental and social contexts, a tipping point is typically seen as a threshold after which a small change can lead to drastic and often irreversible shifts. Positive tipping points, however, refer to the transitions that create beneficial, self-reinforcing cycles—turning the momentum towards achieving climate goals. These might be driven by policy changes, technological advancements, or shifts in cultural norms and behaviors.

2. **Importance**:
- **Accelerated Action**: By reaching these positive feedback loops, societies can quickly and effectively transition to renewable energy sources and sustainable practices.
- **Behavioral and Policy Shifts**: Positive tipping points often rely on behavioral changes or policy shifts that trigger broader changes, making them vital for large-scale transformation.
- **Exponential Impacts**: Once initiated, these tipping points can lead to exponential growth in climate action benefits, significantly reducing the time needed to achieve climate targets.

While the initial research and discussion around tipping points often focused on their negative aspects—such as irreversible environmental damage—recognizing and fostering positive tipping points is crucial for sustainable development and mitigating climate change impacts [source: TheBulletin.org].

Questions

For Environmentalists

• What exactly are climate tipping points, and how do they differ from gradual changes in the climate? Understanding these critical thresholds can help us grasp the intensity of potential climate shifts. Can you explain the mechanisms that lead to these tipping points being crossed?Gemini
• How do I identify the key climate tipping points that could impact my local ecosystem? It’s crucial for environmentalists to recognize these turning points to advocate effectively for policy changes. What resources or tools can assist in monitoring these specific indicators?Gemini
• What are the main differences between climate tipping points and feedback loops in climate systems? While both concepts are vital in understanding climate change, they play different roles in the overall process. How can distinguishing between them enhance our strategies for mitigation?Gemini
• Why is it that some climate solutions seem to stall or fail in preventing the crossing of tipping points? It can be frustrating to see well-intentioned efforts not yield the desired outcomes. What common pitfalls should environmentalists be aware of when implementing climate action initiatives?Gemini
• What is the best way to communicate the urgency of climate tipping points to the general public? Engaging storytelling and clear visuals can make complex scientific concepts more relatable. How can we leverage social media effectively to raise awareness and drive action around this critical issue?Gemini

For Governments

• What exactly are climate tipping points, and how do they differ from other climate change indicators? Understanding their definition is crucial for policymakers as they represent thresholds that, once crossed, can lead to irreversible environmental changes. Can we quantify their impact on ecosystems and human societies?Gemini
• How do I effectively communicate the dangers of climate tipping points to my constituents? It’s essential to frame these issues in a way that resonates with the public and drives action. What strategies can I use to foster understanding and urgency around this critical topic?Gemini
• What are the key differences between various climate tipping points, such as ice sheet melting versus ocean acidification? Recognizing these distinctions can help governments prioritize their responses and allocate resources more effectively. How can we leverage this knowledge to create more targeted climate policies?Gemini
• Why is our current climate policy not adequately addressing the risk of reaching tipping points? Many existing regulations may not fully account for the cumulative and interconnected nature of these risks. What adjustments can be made to ensure that our strategies are more proactive and preventative?Gemini
• Is it true that some climate tipping points may have already been crossed, and what does this mean for future policy development? Understanding the current state of these thresholds is crucial for forecasting potential climate scenarios. How should this information influence our long-term planning and international climate agreements?Gemini

For Universities

• What are climate tipping points, and how do they differ from other environmental thresholds? Understanding the mechanisms behind these tipping points is crucial for comprehending their potential impacts. Can you explain how they can lead to irreversible changes in our climate systems?Gemini
• How do I assess the likelihood of reaching a climate tipping point in my research? It’s important to identify the variables and models that can predict these critical thresholds. What methodologies or tools can I use to analyze this risk effectively?Gemini
• What are the implications of crossing a climate tipping point compared to maintaining a stable climate? Exploring the differences in outcomes can provide insights into the urgency of climate action. How do these implications vary geographically and socio-economically?Gemini
• Why is the current scientific consensus on climate tipping points not leading to more immediate action? Despite widespread awareness, there seems to be a disconnect between knowledge and policy implementation. What are the barriers that prevent effective responses to these critical environmental thresholds?Gemini
• Is it true that some climate tipping points are already being crossed, and what does that mean for the future? This question challenges the notion of when these tipping points will occur and highlights their potential immediate impacts. What evidence do we have to support this claim, and how can it influence future climate strategies?Gemini

For Scientists

• What exactly are climate tipping points, and how do they differ from gradual climate changes? Understanding the specific mechanisms and thresholds involved in these tipping points is crucial for scientists studying climate dynamics. Can we quantify the risks associated with each identified tipping point, and how does this influence our overall climate models?Gemini
• How do I effectively communicate the urgency of climate tipping points to policymakers and the general public? It can be challenging to convey the complex scientific concepts in a way that resonates with non-experts. What strategies have proven successful in translating the implications of these tipping points into actionable policy recommendations?Gemini
• What are the key differences between the melting of polar ice caps and the thawing of permafrost as climate tipping points? Both phenomena have significant implications for global sea levels and greenhouse gas emissions, but they operate under different mechanisms. How does understanding these differences help in predicting their respective impacts on future climate scenarios?Gemini
• Why is the current understanding of climate tipping points not leading to more decisive action in climate policy? Despite a growing body of research indicating the potential for catastrophic outcomes, many nations still hesitate to implement necessary changes. What factors contribute to this disconnect between scientific knowledge and political action?Gemini
• What is the future of our planet if we exceed critical climate tipping points, and which scenarios are most likely to unfold? As scientists, we need to explore the long-term ecological and societal impacts of crossing these thresholds. How can we better prepare for and mitigate these potential outcomes through research and innovation?Gemini

For Students

• What are climate tipping points, and how do they differ from other environmental changes? Understanding the concept of tipping points is crucial for grasping the urgency of climate change. Can you explain the mechanisms behind these tipping points in a way that’s relatable for students?Gemini
• How do I recognize the signs that a climate tipping point is approaching? Identifying early warning signs can be complex, but it’s essential for awareness and activism. What are some practical ways I can monitor these changes in my local environment or globally?Gemini
• What’s the difference between feedback loops and climate tipping points? Both concepts are related to climate change, but they have distinct implications for our planet's future. How do these two concepts interact to influence environmental stability?Gemini
• Why is it that some climate models predict different outcomes regarding tipping points, and what does that mean for our understanding of climate change? This variation in predictions can often be confusing and may lead to skepticism. How can we discern which models provide the most reliable information?Gemini
• Is it true that if we reach certain climate tipping points, we might not be able to reverse the damage? This question raises concerns about the long-term viability of our planet’s ecosystems. What evidence supports or contradicts this idea, and how can students advocate for preventive measures?Gemini

For Journalists

• What are climate tipping points, and how do they differ from other climate change thresholds? Understanding these critical thresholds is essential for journalists reporting on environmental issues. Can you explain the mechanisms behind these tipping points and their potential impacts on ecosystems and human societies?Gemini
• How do I effectively communicate the urgency of climate tipping points to my audience without inciting panic? It's crucial for journalists to strike a balance between raising awareness and providing actionable insights. What strategies can I use to frame these complex concepts in a way that engages and informs readers?Gemini
• How do the risks associated with climate tipping points compare to more gradual climate changes? Journalists often need to highlight the differences in urgency and potential consequences between these two phenomena. What are the key factors that make tipping points particularly alarming for our planet's future?Gemini
• Why is it that some climate models fail to accurately predict the onset of tipping points? Understanding the limitations of current models is vital for journalists who aim to report on climate science accurately. Can you shed light on the challenges scientists face in forecasting these critical transitions in climate systems?Gemini
• What is the best way to convey the potential future scenarios resulting from climate tipping points to a general audience? Journalists play a crucial role in shaping public perception and understanding of climate risks. How can I use storytelling techniques to illustrate these scenarios compellingly and effectively?Gemini

For Activists

• What are climate tipping points and how do they differ from gradual climate changes? Understanding the distinction can help activists convey the urgency of addressing these critical thresholds. Can you explain how these points lead to irreversible changes in our environment?Gemini
• How do I effectively communicate the dangers of climate tipping points to my community? Finding the right language and framing can make a significant impact on awareness and engagement. What strategies can I employ to inspire action against these threats?Gemini
• What is the difference between the melting of polar ice caps and the collapse of the Amazon rainforest in terms of climate tipping points? Both events have severe implications for global ecosystems, but their effects are distinct. How can activists highlight these differences to raise awareness?Gemini
• Why is it that many people still underestimate the risks associated with climate tipping points? There seems to be a disconnect between scientific findings and public perception, which can hinder effective advocacy. What can we do to bridge this gap and foster a deeper understanding of these critical issues?Gemini
• What is the future of our planet if we surpass several climate tipping points? Exploring potential scenarios can motivate others to take action and support environmental initiatives. How can activists create compelling narratives about these futures to galvanize public support?Gemini

For Thought Leaders

• What exactly are climate tipping points, and why are they critical to understanding our planet's climate system? I’ve heard varying definitions, but I want to grasp their implications on a systemic level. How do these tipping points relate to the broader narrative of climate change and sustainability?Gemini
• How can I effectively communicate the urgency of climate tipping points to my audience without overwhelming them? I want to ensure that my messaging resonates and inspires action. Are there specific frameworks or narratives that can help convey complex scientific concepts in an engaging way?Gemini
• What are the key differences between climate tipping points and other climate change indicators, such as thresholds or feedback loops? Understanding these distinctions seems vital for thought leadership in environmental discussions. How do these concepts interconnect and influence policy-making and public awareness?Gemini
• Why is our current approach to mitigating climate change not preventing the risk of reaching tipping points? It feels like despite our efforts, we're still facing severe consequences. What are the systemic barriers or misconceptions that are hindering effective action?Gemini
• What does the future hold for our planet if we continue to ignore the risks associated with climate tipping points? As thought leaders, we need to envision potential scenarios to advocate for change effectively. How can we use foresight to inform policy and drive collective action?Gemini

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