气候行动的积极临界点：更便宜、更清洁、势不可挡的清洁技术

Cheaper. Cleaner.Unstoppable. Clean technologies that aredelivering for the climate 1. Positive tipping points and theirstrategic potential1 Climate impacts are intensifying, and global temperatures are likely to exceed 1.5 degrees Celsius (°C) withinthe next decade (United Nations Environment Programme [UNEP] 2025a). Delivering on the Paris Agreementwill require immediate action to reduce greenhouse gas emissions. In doing so, we can limit peak warming. Recent trends indicate that many low-carbon technologies and behaviours are no longer just emerging.Across energy, transport, buildings, and food systems, several low-carbon technologies and practices areapproaching, and in some cases have already crossed, critical thresholds at which adoption can acceleraterapidly and become increasingly self-reinforcing. These “positive tipping points” arise when reinforcing feedback, including declining costs, infrastructureexpansion, policy support and shifting market expectations, drive nonlinear rates of uptake beyond thoseanticipated by linear predictions (University of Exeter 2023). If supported through sustained policy, finance,and institutional action, these dynamics could contribute to limiting temperature exceedance, strengtheningadaptation to unavoidable climate impacts and supporting pathways consistent with returning warming to1.5°C above pre-industrial levels over the longer term. A positive tipping point is reached when a clean technology, practice or behaviour becomes increasinglyaffordable, competitive and socially accepted, leading to rapid and self-reinforcing uptake (Lentonetal., 2025a, OECD 2025a). Adoption typically follows an S-curve: slow initial uptake, followed by rapidacceleration once affordability, accessibility and attractiveness align, before stabilizing at scale (see Figure1). Crucially, positive tipping points can cascade2across sectors, for example, cheap renewable electricityaccelerates the deployment of electric vehicles and heat pumps, while sustainable food systems reduceemissions and improve food security. Adapted from:Lentonet al., 2025 Note: The sectors labelled above the curve relate to global progress, whereas the examples labelled underthe curve illustrate the range of progress at the national level in just one of those sectors (electric cars). The period to 2030 is decisive. Many clean technologies are at or near cost parity with fossil-basedalternatives and are less exposed to external price volatilities (Nijsse,et al., 2024). Solar power is now cheaperthan new coal and natural gas in most of the world. Electric vehicles have crossed affordability thresholdsin leading markets on a lifetime-cost basis (BloombergNEF 2025). Heat pumps are increasingly cost-competitive with fossil boilers. These trends suggest that rapid, system-wide decarbonisation is within reach,if supported by the right policy and investment signals. However, tipping points do not occur automatically or uniformly. Deliberate and coordinated interventionsby governments, financial institutions, businesses, private sector, civil society and citizens can accelerateor stall their emergence (Smith,et al., 2026). Policy certainty, targeted public finance, regulatory reform,procurement commitments and shifts in consumer behaviour can collectively push systems past criticalthresholds. Embedding tipping point strategies into national climate plans3offers a powerful way to convertclimate ambition into reality. (University of Exeter, 2023). This Policy Brief highlights sectors where positive tipping dynamics are under way, identifies their enablingconditions and proposes actionable steps. Equity is central to this agenda. Positive tipping dynamicswill need to scale globally and not concentrate only in leading and often higher-income countries. Theywill need to deliver benefits across countries, regions and social groups, rather than reinforcing existinginequalities (Pereiraet al., 2024). Expanding access to affordable clean technologies in emerging marketsand low-income communities is essential for both climate effectiveness and fairness, while also deliveringco-benefits such as improved air quality, energy security and economic opportunity. It is imperative that thiseffort is distributed across income strata and geographies, and a gender-responsive approach is essential toensure equitable outcomes. Three features make positive tipping points particularly relevant: 1.Affordability thresholds are being crossed:Clean alternatives are already cost-competitive with, oreven cheaper than, fossil-based incumbents. These trends signal that structural economic conditions arealigning with climate objectives. 2.High diffusion potential:Many clean technologies are modular, mass-producible and compatible withdigital innovation. They can scale rapidly once supply chains mature and financing barriers fall. 3.A narrowing policy window:The 2026–2030 period is pivotal for implementation and investmentalignment as governments