To keep global warming well under 2 degrees Celsius (3.6 degrees Fahrenheit), a drastic acceleration is needed in climate action. To stabilize temperatures within safe limits, greenhouse gas emissions need to be halved by 2030 and reach net-zero by mid-century (IPCC, 2018).

Instead, emissions continue to rise. Sustained global temperatures above 1.5 degrees Celsius (2.7 degrees Fahrenheit) are close to being reached, risking a plethora of climate and ecological tipping points, where changes become self-perpetuating and irreversible.

At first glance, progress may seem incredibly slow. However, a deeper look at how new technologies are adopted and break through to wide acceptance offers a glimmer of hope.

The dynamics of negative Earth system tipping points may also apply to social and economic solutions, where a transition to clean technology or behavior can become self-sustaining and difficult to reverse. These are “positive tipping points”—desirable if we wish to stabilize emissions to limit climate change (Powell et al, 2023).

Often, the uptake of new technologies follows an S-curve: Initially, few people buy a new product, because they are typically more expensive, and may not work that well yet. For instance, few people had the money to buy a color television when it first came out—and because few people had one, broadcasters offered only a limited number of TV programs in color. But over time, a technology becomes more attractive and more affordable—making it more enticing for broadcasters to offer more TV shows in color, in this example. This leads to a virtuous cycle; after a slow start, there is a rapid acceleration. (Though even after most people have switched, there may still be a smaller group of laggards that stick with the old product—for instance, because they don’t watch a lot of TV, or are happy watching in black-and-white.)

The tipping point towards the new configuration is crossed when the self-reinforcing feedbacks become much stronger than the balancing feedbacks. In climate, an example of such a self-reinforcing feedback is what happens when ice melts: The exposure of the underlying sea or ground reduces sunlight reflection, leading to additional warming and further melting.

Social and economic systems have similar feedbacks. Think about economies of scale, making products cheaper when they’re sold more. Or social contagion, where people buy more if they see their neighbors with a new product.

A prevalent idea within climate mitigation economics is that switching to clean technologies is costly. According to this thinking, then, the best strategy is to start with the no-regret options (like applying insulation, replacing old incandescent light bulbs with LEDs, and so forth) and only when you have achieved these options, continue with the more expensive technologies. A carbon tax is raised each year, so that it becomes attractive for more and more of these “difficult-to-decarbonize” sectors to make the switch. In this paradigm, if the carbon tax is removed, the economy starts moving back to the old polluting technologies. Getting rid of fossil fuels therefore would become more difficult each year. The philosophy is that having a single carbon tax is policy neutral, as all industries pay the same per ton of carbon dioxide emissions.

Positive tipping point processes

The key problem with the above paradigm is its lack of focus on change and innovation. A technology improves when people start using it at scale, and they develop habits, infrastructure, and laws around it. Frequently, these changes are so strong that further uptake becomes self-perpetuating.

Various processes can give rise to these self-reinforcing feedbacks. Two key ones are related to costs. New technologies usually become cheaper due to research-and-development investments and learning-by-doing: The more you deploy of a technology, the more attractive it is to invest in R&D for it, and the more your costs come done due to a more experienced work force.

Technologies typically also become cheaper when created at scale. For instance, battery prices fell by 90 percent between 2010 and 2020.

Network effects play a key role in electric vehicle (EV) adoption. When very few people own an EV, there is little incentive for companies or authorities to install public chargers and therefore it’s less attractive to buy an EV, as you might become stranded on longer trips—an aversion known as “range anxiety.” When more people buy EVs, the network of charging points becomes denser, and you’re more likely to find a charging point, which solves the range anxiety problem. This network effect makes people more likely to use or own EVs. (For e-bikes, a similar story unfolds where they become more attractive for longer trips as the charging network is built out.)

Social contagion is another key process. After one household in a neighborhood adopts solar panels, their neighbors are more likely to do the same in the following year (Baranzini et al, 2017). The first household may recommend a good installer or show neighbors directly how much their electricity bills have come down. Similarly, companies are more likely to adopt solar panels if other nearby companies do the same.

Social contagion and network effects also play a role in the transition to walkable and cyclable cities. If more people cycle, the reduction in cars makes it safer for others to pick up the habit. And if more bike paths are built, this improves connectivity in the city, making  walking and biking easier.

A technology can experience a tipping point at its beginning (phase-in) and also at its end (phase-out). When EVs vastly outnumber fossil-driven cars, it’s more difficult to make gasoline stations profitable. The fossil fuel infrastructure becomes too expensive to maintain, and network density goes down, making it tougher to find somewhere to fill up your car.

But before any of this can happen, many sectors have strong balancing feedbacks resisting system change—and these balancing feedbacks need to be overcome. For instance, countries may want to protect jobs in fossil industries. In Germany, a rapid phase-out of petrol and diesel cars would likely cost many jobs, as EVs are easier to produce, and Germany lags behind China in the production of electric vehicles. In response, the German government requested an exception for “e-fuels” in the European 2035 combustion car phase-out.

A further balancing feedback comes from the response of existing industries, who seek to stop green competition. One common strategy of such industries is to weaponize print (sometimes known as “legacy”) media and social media, creating and spreading disinformation about green technologies—for instance, spreading the myth that heat pumps do not work in cold weather.

The story becomes even more interesting when we examine the concept of cascading tipping points (Nijsse, 2024). There may be changes in one sector—cheaper and more efficient residential rooftop solar panels, for instance—that lead to a tipping point in which more people get their energy from rooftop solar. (The National Renewable Energy Laboratory notes that there has been a 64 percent drop in the cost of residential solar systems since 2010 and a consequent upsurge in the installation of home solar systems [NREL, 2021]). In turn, this drives the demand for better home batteries to store the energy that has been generated from the solar panels. Without the innovation from electric car uptake, these batteries would likely be too expensive. Applications at home further stimulate innovation in efficiency, longevity, and the manufacturing of batteries. This opens up the possibilities for using batteries in electric trains, electric ships, and large trucks. Consequently, advances in one sector can ultimately enable a series of positive tipping points in other sectors (Eker et al, 2024). (See figure 1.)

The story of solar power

The solar revolution is a key example of such a positive tipping point.

In the 1970s, the world reeled from the oil crisis, when OPEC members boycotted countries supporting Israel in the Yom Kippur War. Many governments began programs to improve energy efficiency and explore alternative energy sources. In 1974, Japan launched its “Sunshine Project,” a large R&D project for alternative energy sources, and in the 1990s the country got serious about stimulating rooftop solar demand (Nemet, 2019). A solar panel in 1975 was over 500 times as expensive as it was at the beginning of the 2020s, so betting on it back then took courage. Its cost was so high that a carbon tax alone could never have made it competitive with fossil fuel alternatives.

A decade later, Germany repeated this policy of stimulating R&D and deployment in their Energiewende policy push.

Costs for generating electricity from solar cells declined dramatically—from hundreds of dollars per watt in the ‘70s to an average of about 20 to 30 cents per watt in 2023 (Avenston, 2023)—and solar evolved from a niche technology for consumer electronics and satellites, to something that can power a whole household. In 2020, the International Energy Association declared solar power to be the cheapest form of electricity in history (Evans, 2020). Given these cost declines, it’s difficult to imagine solar not becoming the dominant form of electricity generation by mid-century (Nijsse et al, 2023). (See figure 2 below.)

One of the key feedbacks behind the success of solar is its amazingly steep experience curve. For each doubling of capacity, the price of solar falls by around 20 percent (Roser, 2023). Initially, when there are only few panels on the market, it’s easy to double the global capacity and prices fall rapidly. With more experience, prices still go down each year—if more slowly. This exponential learning-by-doing, or “Wright’s law,” is observed for many technologies, including washing machines, TVs, and wind turbines, but cost decline per doubling is different for each technology. Solar is very near the top. The modular nature of solar panels is part of the explanation for why costs are coming down so fast, as it enables mass production. By contrast, each nuclear power plant needs to be redesigned, making its construction less like mass production and more akin to the making of a bespoke tailored suit.

This modularity in the solar energy field also means that new applications are found all the time, further strengthening deployment. For instance, in a move that brings solar power firmly in reach of renters, 1.5 million German households(Burgen, 2024) have installed solar panels on their balconies. Often, these systems can be simply plugged in, without the need for complicated installations.

It is noteworthy that policy in a handful of countries—often quite expensive policy—set a transition in motion worldwide that transformed solar power into the cheapest source of electricity, significantly expanding access to energy.

International cooperation in a world of tipping points

So, how should international climate policy change if we look at climate action through the positive tipping point lens? The yearly international climate summit, the Conference of Parties, or COP, seeks to make decisions by consensus. That is, all countries need to align. In practice, this means that the ambition level is set at the lowest common denominator, so oil-producing countries like Russia and Saudi Arabia can sign off on it too.

But to improve new technologies and bring down their costs, not all countries need to sign on immediately. The electric vehicle breakthrough was achieved, without much coordination, by complementary policies in California, Norway, and the Netherlands. In California, sales mandates starting in the 1990s forced car manufacturers to develop electric cars. In contrast, Norway—and to a lesser extent the Netherlands—implemented highly attractive tax breaks for electric car drivers.

The speed of this early transition was slow, just like it was slow for the solar power breakthrough. If we’re serious about limiting global warming, coordination is needed.

With this in mind, at the 2021 COP26 in Glasgow, a new strategy was implemented in the form of the Breakthrough Agenda (IEA, 2024). For each major emitting sector, a coalition of the willing was created. For instance, to clean up buildings in colder climates, the “Clean Heat Forum” was created, trying to coordinate standards and mandates to drive down heat pump and deep retrofit costs. Other countries are involved in collaborations around cement, road vehicles, and cooling.

What these collaborations have in common is their ability to target sensitive intervention points. In each sector this is different (Nijsse, 2024). In road freight and power generation, a carbon tax is highly effective. In consumer-facing sectors such as home heating or buying a car, a carbon tax helps level the playing field, but subsidies may play a stronger role. In most sectors, mandates to phase-out fossil technology and phase-in clean technology are likely highly effective, especially when coordinated to maximize cost declines.

Are positive tipping points truly irreversible?

In nature, laws cannot be broken. A tipping point of Amazon rainforest dieback or the collapse of the Atlantic Meridional Overturning Circulation can be truly irreversible on human timescales. When we talk about socio-economic positive tipping points, however, things can become blurry. For instance, in the United Kingdom, the cheapest form of electricity production—onshore wind—was de facto banned for a decade (2015–2024) until the ban was removed by the new Labour government (Horton, 2024).

Unlike nature, society is not subject to immutable laws. Even when all the economic stars align—as they do for wind, solar, and batteries—fossil fuel incumbents can lobby or buy elections to ban new technologies that threaten their interests. Progress might continue in countries with less fossil fuel interests, typically countries that need to import oil and gas, but ultimately, we do need global action to get climate change under control.

Not all changes required to keep warming well under 2 degrees Celsius are likely to have these self-reinforcing feedbacks. For instance, it is difficult to identify strong feedback processes in building insulation. People often report that a (deep) retrofit is too disruptive for their daily lives, even if it makes economic sense in the long run. Good building insulation is, however, an enabling factor for other tipping points, as it reduces seasonal peaks in electricity demand (lowering overall costs) and makes heat pumps more efficient. Houses may even become thermal batteries when they’re well-insulated: You can heat them when electricity prices are low at night, and, due to the insulation, it retains the energy throughout the day.

What have we learned?

Positive tipping points can help accelerate clean energy and other sustainability transitions. Thinking about it in this way helps us define more effective international coordination, where a coalition of the willing sets standards and drives down costs for a chosen technology. It helps us formulate more effective national policies—for example, governments driving initial deployment to kickstart processes of social contagion, network formation, and learning-by-doing.

If we map out, sector by sector, how specific policies can be amplified by economic and social dynamics, we can choose the most effective policies. Often, this will be a combination of stick and carrot: A carbon tax in combination with a more direct policy to encourage deployment, such as government procurement in the early stages. And as time goes by, other approaches, such as mandates and phase-outs, become more effective. These policies pay off, especially as we move to the steep part of the S-curve. Progress may seem slow, but in sectors where we’re hitting tipping points, the acceleration is happening. For others with tipping potential, we can adapt this blueprint, drawing lessons from the success of EVs and solar power.