A – Current Status and Trends

Observed Warming and Its Causes

1. Human activities, primarily through greenhouse gas emissions, have unequivocally caused global warming, with a global surface temperature reaching 1.1°C above 1850-1900 between 2011-2020. Global greenhouse gas emissions have continued to increase, with historical and current contributions being uneven due to unsustainable energy use, land use and land use change, lifestyle and consumption patterns across regions, countries, within countries, and among individuals.

Observed Changes and Impacts

2. Widespread and rapid changes have occurred in the atmosphere, oceans, cryosphere, and biosphere. Human-caused climate change is already affecting many extreme weather and climate events across all regions of the world. This has led to widespread adverse impacts and nature-related and human-related losses and damages. Vulnerable communities, which historically have contributed less to current climate change, are disproportionately affected.

Current Progress in Adaptation and Gaps and Challenges

3. Adaptation planning and implementation have progressed across sectors and regions, with documented benefits and varying effectiveness. Despite progress, adaptation gaps exist and will continue to grow at the current pace of implementation. Rigid and soft adaptation limits have been reached in some ecosystems and regions. Poor adaptation is occurring in some sectors and regions. Current global financial flows for adaptation are insufficient and limit the implementation of adaptation options, especially in developing countries.

Current Advances, Gaps, and Challenges in Mitigation

4. Policies and laws addressing mitigation have steadily expanded since AR5. Global greenhouse gas emissions in 2030 implied by the Nationally Determined Contributions (NDCs) announced in October 2021 make it likely that warming will exceed 1.5°C during the 21st century and will hinder limiting warming to below 2°C. There are gaps between projected emissions from implemented policies and those from NDCs, and financing flows are not reaching the levels needed to meet climate goals across all sectors and regions.

B – Future Climate Change, Risks, and Long-term Responses

Future Climate Change

1. Continuous greenhouse gas emissions will lead to an increase in global warming, with the best estimate reaching 1.5°C in the near term in considered scenarios and modeled pathways. Each increment of global warming will intensify multiple and simultaneous hazards. Deep, rapid, and sustained reductions in greenhouse gas emissions would lead to a noticeable slowdown in global warming within about two decades, and also to noticeable changes in atmospheric composition in a few years.

Impacts of Climate Change and Climate-Related Risks

2. For any given level of future warming, many climate-related risks are greater than those assessed in AR5, and projected long-term impacts are up to several times greater than those currently observed. Projected climate risks and adverse impacts, as well as climate-related losses and damages, increase with each increment of global warming. Climate and non-climate risks will increasingly interact, creating compound and cascading risks that are more complex and difficult to manage.

Probability and Risks of Inevitable, Irreversible, or Abrupt Changes

3. Some future changes are inevitable and/or irreversible but can be limited by deep, rapid, and sustained global reductions in greenhouse gas emissions. The probability of abrupt and/or irreversible changes increases with higher levels of global warming. Similarly, the probability of low-probability outcomes associated with potentially very large adverse impacts increases with higher levels of global warming.

Adaptation Options and Their Limits in a Warmer World

4. Adaptation options that are feasible and effective today will become limited and less effective with increasing global warming. As global warming increases, losses and damages will rise, and additional human and natural systems will reach adaptation limits. Poor adaptation can be avoided through flexible, multisectoral, inclusive, and long-term adaptation planning and implementation, with co-benefits for many sectors and systems.

Carbon Budgets and Net Zero Emissions

5. Limiting human-caused global warming requires net-zero CO2 emissions. The cumulative carbon emissions until reaching net-zero CO2 emissions and the level of reduction of greenhouse gas emissions this decade largely determine whether warming can be limited to 1.5°C or 2°C. Projected CO2 emissions from existing fossil fuel infrastructure without further reduction would exceed the remaining carbon budget for 1.5°C (50%).

Mitigation Pathways

6. All globally modeled pathways that limit warming to 1.5°C (>50%) without exceeding it, and those that limit warming to 2°C (>67%), involve rapid and deep greenhouse gas reductions, and in most cases, immediate reductions across all sectors this decade. Global net-zero CO2 emissions are reached for these pathways by the early 2050s and around the early 2070s, respectively.

Overshoot: Surpassing a Level of Warming and Returning

7. If warming exceeds a specific level, such as 1.5°C, it could be gradually reduced back by achieving and maintaining global net negative CO2 emissions. This would require additional carbon dioxide removal deployment compared to non-overshoot pathways, raising concerns about feasibility and sustainability. Overshoot entails adverse impacts, some irreversible, and additional risks to human and natural systems, all increasing with the magnitude and duration of the overshoot.

C – Short-Term Responses

Urgency of Integrated Short-Term Climate Action

1. Climate change is a threat to human well-being and the health of the planet. There is a rapidly closing window of opportunity to secure a livable and sustainable future for all. Climate-resilient development integrates adaptation and mitigation to advance sustainable development for all, and is enabled by increased international cooperation, including better access to adequate financial resources, particularly for vulnerable regions, sectors, and groups, and inclusive governance and coordinated policies. The options and actions implemented in this decade will have an impact now and for thousands of years.

Benefits of Short-Term Action

2. Deep, rapid, and sustained mitigation and accelerated implementation of adaptation actions this decade would reduce projected losses and damages to humans and ecosystems and generate many co-benefits, especially for air quality and health. Delayed mitigation and adaptation measures would lock in high-emission infrastructure, increase risks of stranded assets and cost escalation, reduce viability, and increase losses and damages. Short-term actions involve large initial investments and potentially harmful changes that can be mitigated through a range of favorable policies.

Mitigation and Adaptation Options Across Systems

3. Rapid and far-reaching transitions across all sectors and systems are needed to achieve deep and sustained emission reductions and ensure a livable and sustainable future for all. These system transitions involve significant improvements in a broad portfolio of mitigation and adaptation options. Feasible, effective, and low-cost options for mitigation and adaptation are already available, with differences across systems and regions.

Synergies and Trade-offs with Sustainable Development

4. Accelerated and equitable action to mitigate and adapt to the impacts of climate change is essential for sustainable development. Mitigation and adaptation actions have more synergies than trade-offs with the Sustainable Development Goals. Synergies and trade-offs depend on context and scale of implementation.

Equity and Inclusion

5. Prioritizing equity, climate justice, social justice, inclusion, and just transition processes can enable ambitious adaptation and mitigation actions and climate-resilient development. Adaptation outcomes are enhanced by increased support to regions and people with the highest vulnerability to climate hazards. Integrating climate adaptation into social protection programs enhances resilience. Many options are available to reduce emission-intensive consumption, including through behavioral and lifestyle changes, with co-benefits for social well-being.

Governance and Policies

6. Effective climate action is made possible by political commitment, well-aligned multi-level governance, institutional frameworks, laws, policies, and strategies, and better access to finance and technology. Clear goals, coordination across multiple policy domains, and inclusive governance processes facilitate effective climate action. Regulatory and economic instruments can support deep emission reductions and climate resilience if scaled up and widely implemented. Climate-resilient development benefits from leveraging diverse knowledge.

Finance, Technology, and International Cooperation

7. Finance, technology, and international cooperation are critical enablers to accelerate climate action. To achieve climate goals, both adaptation and mitigation financing would need to be scaled up. There is sufficient global capital to close global investment gaps, but barriers exist in redirecting capital toward climate action. Improving technological innovation systems is key to accelerating widespread adoption of technologies and practices. Enhanced international cooperation through multiple channels is possible.