Rotterdam sits below sea level, home to more than a million people and one of the world's largest ports. Its main defense against a North Sea storm surge is a single piece of infrastructure: the Maeslantkering, two enormous steel gates, each 210 meters wide, that normally sit open to let ships through.
Is building a barrier like this "solving" climate change, or something else entirely?
Why this has to be a global response
To avoid the risk of catastrophic climate change, global action is required, rather than measures adopted only by certain states. Because greenhouse gases mix throughout the whole atmosphere within one to two years of being released, one country's emissions affect every other country's climate, regardless of where those emissions originated. This is what economists call a global public good problem: the atmosphere cannot be divided into national sections, so no single country acting alone can stabilize the climate on its own, and every country has an incentive to let others cut emissions first while it keeps burning fuel cheaply, a dynamic often called free-riding.
This creates tension with state sovereignty: countries are reluctant to have their domestic energy and industrial policy dictated by international agreement, so effective global action depends on negotiation through treaties, protocols and conventions rather than enforcement by any higher authority. The United Nations Framework Convention on Climate Change (UNFCCC), signed in 1992, set up the ongoing negotiation process itself, and the Paris Agreement, adopted in 2015 under that framework, is the current global treaty: 196 parties agreed to hold warming well below 2°C above pre-industrial levels, but each country submits its own voluntary Nationally Determined Contribution rather than accepting a legally binding national target, precisely because full sovereignty over domestic policy was the price of getting near-universal participation. Where voluntary cooperation looks insufficient, some countries have started backing agreements with harder consequences, such as the European Union's Carbon Border Adjustment Mechanism, which taxes imports of steel, cement and other goods from countries with weaker carbon pricing so that domestic producers facing a carbon price are not undercut by cheaper, higher-emission imports.
Decarbonization and carbon neutrality
Decarbonization means reducing or ending the use of energy sources that result in CO2 emissions, replacing them with renewable energy sources instead. Countries set varied target dates for reaching carbon neutrality, the point at which any remaining emissions are balanced by removals.
- Bhutan has already achieved carbon negative status: its vast forest cover absorbs more CO2 than the country emits.
- Sweden has set 2045 as its legally binding target, the earliest legislated date of any major economy.
- Norway has legislated a 2050 target, the same date set by the large majority (over 90%) of the more than 130 countries that have made a formal carbon neutrality commitment.
Sources: World Economic Forum; Energy & Climate Intelligence Unit (ECIU) Net Zero Tracker.
Three categories of mitigation strategy
There are three main categories of mitigation strategy. Sort each real example below into the category it belongs to.
Reflective aerosols are injected into the stratosphere to reflect a small amount of incoming sunlight back to space.
A national government introduces a tax on each tonne of CO2 a company emits.
A large-scale afforestation project replants a previously deforested watershed.
A country replaces coal power plants with wind and solar farms.
Adaptation: structural and non-structural
Adaptation strategies aim to reduce the adverse effects of climate change and maximize any positive consequences. There are two main categories: structural adaptations, physical infrastructure such as flood defenses, desalination plants and movable infrastructure, and non-structural changes, such as adapting agricultural practices with drought-resistant crops, vaccination programs for new diseases, land zoning and building code changes.
The Maeslantkering from this subtopic's hook is the clearest possible example of a structural adaptation: purpose-built physical infrastructure that manages a consequence of climate change without touching its cause.
Application of skills, statement 6.3.4: create a survey to investigate attitudes to a proposed climate mitigation solution in your school or community. A full walkthrough of survey-design practice is built out on the Skills tab.
National and local adaptation plans
Individuals and societies at a range of scales are developing formal adaptation plans, such as National Adaptation Programmes of Action (NAPAs), along with broader resilience and adaptation plans. The UN Development Programme (UNDP) provides a process through which developing countries can access assistance to develop local priority activities addressing the most imminent consequences of climate change in their own context. NAPAs were created specifically for the least developed countries (LDCs), the group of nations with the fewest financial and technical resources to adapt on their own, and each plan is built from local consultation rather than being imposed from outside: communities identify which climate risks threaten them most urgently, whether that is drought affecting food security, sea-level rise threatening coastal settlements, or more frequent flooding, and the resulting NAPA ranks adaptation projects by urgency so that limited international finance goes to the most pressing need first.
Adaptation planning also happens well below the national level. City and municipal governments increasingly write their own local adaptation strategies, since flood risk, heat exposure and water supply vary enormously between a coastal city and an inland one even within the same country. The Netherlands' Room for the River program, discussed on the Learn tab, is itself a national plan implemented through dozens of separate local projects, each tailored to the specific stretch of river and community it protects. This layered structure, from UNFCCC-level negotiation down to a single municipality's flood plan, reflects the reality that climate impacts are experienced locally even though the gases that cause them mix globally.
- Maeslantkering flood barrier: Rijkswaterstaat (Dutch Ministry of Infrastructure and Water Management).
- Carbon neutrality target dates: World Economic Forum; Energy & Climate Intelligence Unit (ECIU) Net Zero Tracker.
- IB Environmental Systems and Societies Guide, first assessment 2026, Topic 6, Subtopic 6.3, statements 6.3.1-6.3.5.
Designing a survey that measures attitudes fairly
Application of skills, statement 6.3.4: create a survey to investigate attitudes to a proposed climate mitigation solution in your school or community, for example, "should the school install solar panels?" A well-designed survey question avoids leading language, avoids asking two things at once, and uses a measurable scale. Sort each draft question below.
"Don't you agree that solar panels would benefit our school?"
"On a scale of 1 (strongly oppose) to 5 (strongly support), how do you feel about installing solar panels on the school roof?"
"Do you support installing solar panels and starting a school composting program?"
"Would you support helping save our planet by installing solar panels at school?"
When asked to design or evaluate a survey, always check for three things by name: leading or loaded language, double-barreled questions, and whether the response scale actually produces usable, comparable data.
- IB Environmental Systems and Societies Guide, first assessment 2026, Topic 6, Subtopic 6.3, statement 6.3.4.
Glossary
- State sovereignty
- A state's supreme authority over its own territory and domestic policy, which creates tension with binding international climate agreements.
- Cross-border carbon tax
- A tariff applied to imports from countries with weaker climate policy, intended to discourage "carbon leakage."
- Decarbonization
- Reducing or ending the use of energy sources that result in CO2 emissions, replacing them with renewable alternatives.
- Carbon neutrality
- A state in which any remaining greenhouse gas emissions are balanced by an equivalent amount of removal.
- Mitigation
- Action that addresses the causes of climate change, typically by reducing or removing greenhouse gas emissions.
- Geoengineering
- Deliberate, large-scale intervention in Earth's climate system, such as stratospheric aerosols or ocean fertilization, that treats the symptoms of climate change rather than its root cause.
- Carbon sink
- A natural or artificial reservoir that absorbs more carbon than it releases, such as a forest or the ocean.
- Afforestation
- The establishment of forest on land that was not previously forested.
- Carbon capture and storage (CCS)
- Technology that captures CO2 emissions at their source and stores them, usually underground, to prevent their release into the atmosphere.
- Adaptation
- Action that reduces the adverse effects of climate change already underway, or that maximizes any positive consequences.
- Structural adaptation
- A physical infrastructure response to climate change, such as a flood barrier or desalination plant.
- Non-structural adaptation
- A policy or practice change in response to climate change, such as a building code update or a new crop variety.
- NAPA
- National Adaptation Programme of Action: a country-level plan, often developed with UN Development Programme assistance, identifying priority actions to address the most urgent climate consequences.
- UNFCCC HL
- United Nations Framework Convention on Climate Change: the treaty aiming to stabilize GHG concentrations at a level that prevents dangerous interference with the climate system.
- IPCC HL
- Intergovernmental Panel on Climate Change: the UN body that synthesizes and assesses climate science to inform policy.
- COP HL
- Conference of the Parties: the annual UNFCCC summit where countries negotiate climate commitments.
- Kigali Amendment HL
- A 2016 amendment to the Montreal Protocol controlling hydrochlorofluorocarbons (HFCs), ozone-safe substitutes that turned out to be potent greenhouse gases.
- HFC HL
- Hydrochlorofluorocarbon: a class of chemical used as a substitute for ozone-depleting substances, later found to be a potent greenhouse gas.
- Emissions scenario HL
- One of several IPCC-modeled pathways (Shared Socioeconomic Pathways, or SSPs) representing a different set of assumptions about future global emissions.
- Tragedy of the commons HL
- The idea that a shared resource, such as the atmosphere, tends to be overused or degraded because the costs of that overuse are shared by everyone while the benefits go to whoever uses it.
- Stakeholder HL
- An individual, group or organization with an interest in, or influence over, a decision or issue.
Test Yourself is coming soon for this subtopic
Practice questions and markschemes for this page are still being written. Check back once they have been added.
Who actually leads a climate response
Responses to climate change may be led by governments or by a range of non-governmental stakeholders, and can take several forms: economic measures (putting a price on carbon, emissions trading, subsidies and tariffs), legislation (country-specific laws reducing carbon emissions), goal-setting commitments (mechanisms like B Corp branding or a company's own emissions targets), and personal life changes (reducing waste, meat consumption or energy use).
A regional government launches an emissions trading scheme, letting companies buy and sell permits to emit CO2.
A transnational company publicly pledges to reach net-zero emissions by 2040.
A national parliament passes a law legally requiring a 50% emissions cut by 2035.
The UN's role: UNFCCC, IPCC and COP
The UN has played a key role in formulating global climate strategy, largely led by the United Nations Framework Convention on Climate Change (UNFCCC) through the Intergovernmental Panel on Climate Change (IPCC) and the annual Conference of the Parties (COP) summits. The UNFCCC's role is to stabilize greenhouse gas concentrations at a level that prevents dangerous interference with the climate system. The Kigali Amendment is a real example of adaptive UN policy: it was used to control hydrochlorofluorocarbons (HFCs), substances originally approved as ozone-safe substitutes under the Montreal Protocol, but which later proved to be potent greenhouse gases in their own right.
- COP30 ran from 10-21 November 2025, with the final political package agreed in overtime on 22 November after negotiations extended nearly a full extra day.
- Key outcomes included a pledge to mobilize $1.3 trillion annually by 2035 for climate action, and to triple adaptation finance for vulnerable countries by 2035.
- New mechanisms included the Tropical Forests Forever Facility, with over $5.5 billion announced and 53 countries endorsing it, and the Belem Mission to 1.5°C.
- A notable shortcoming: the final package did not include a clear, time-bound roadmap for transitioning away from fossil fuels.
Sources: UN News; Carbon Brief; World Resources Institute, COP30 summaries, November-December 2025.
Five futures: the IPCC's emissions scenarios
The IPCC has proposed a range of emissions scenarios with targets to reduce the risk of catastrophic climate change. There is real uncertainty about how emissions by different countries will actually change, so the IPCC's most recent assessment models five Shared Socioeconomic Pathways (SSPs), from a very low future-emissions pathway to a very high one. Application of skills, statement 6.3.8: investigate graphs of the IPCC scenarios and their implications. Match each scenario below to its broad emissions trajectory.
SSP1-1.9
SSP2-4.5
SSP5-8.5
Never describe an IPCC scenario as "the" prediction. Each SSP is one plausible pathway among five, built from different assumptions about global socioeconomic development and policy choices, not a forecast of what will definitely happen.
Technology, and the barriers to using it
Technology is being developed and implemented to aid climate mitigation. Socially embedded technologies include smart city tools, such as mobile apps or sensors directing citizens to the nearest EV charging station or recycling center, often developed through university research and development partnerships with industry. Other examples include smart electricity grids that shift demand to times when renewable supply is highest, building management systems that automatically cut heating and cooling waste, and precision agriculture sensors that reduce fertilizer use and its associated N2O emissions. What makes these "socially embedded" rather than purely technical is that their climate benefit depends on how widely people actually adopt and use them, not just on whether the technology exists.
Why good technology and policy still stall
There are challenges to implementing climate management and intervention strategies, even when the technology or policy design exists: a lack of belief that climate change is a serious problem; a lack of financial resources or planning strategy in national governments; a lack of leadership from stakeholders such as individuals, NGOs, political leaders or transnational companies; international inequalities between economies that profit from fossil fuels and those that do not; and differences in perspective between younger and older generations, and between coastal/low-lying and inland/upland communities.
These barriers rarely act alone. A national government may accept the science but lack the tax revenue to subsidize a nationwide grid upgrade, especially in a lower-income economy already stretched by other development priorities, so a technically sound plan stalls for a purely financial reason. Elsewhere, the technology and the money both exist but local leadership is missing: without a mayor, minister or company willing to spend political capital pushing an unpopular short-term cost (such as a fuel price rise) for a long-term benefit, adoption drifts. Fossil-fuel-exporting economies face a distinct version of the same barrier: their government revenue and employment are often tied directly to oil, gas or coal extraction, so a rapid transition threatens near-term economic stability even when leaders accept the long-term case for it, which is one reason international negotiations move slowly on phasing out fossil fuel subsidies.
Geoengineering: treating the symptom, not the cause
Geoengineering is a deliberate, large-scale intervention in Earth's climate system, including but not limited to space mirrors, ocean fertilization, stratospheric aerosols, cloud seeding, and burning biomass with carbon capture and storage. It is explicitly a mitigation strategy that treats the symptom, warming itself, rather than the underlying cause. It carries disadvantages: potentially very high costs, significant uncertainty about real-world impacts given limited large-scale trials, political hesitancy, and the potential for geopolitical conflict if one country's intervention alters climate conditions for others without their consent.
Quick check: why is geoengineering described as treating a "symptom" rather than a "cause"?
Who shapes perspectives on climate change
A range of stakeholders play an important role in shaping individual perspectives on climate change: a charismatic individual, a local community group, NGOs, media outlets, and educational institutions can all influence how seriously someone treats the issue and which solutions they consider legitimate. A single high-visibility figure, such as a youth climate activist or a scientist who becomes a public communicator, can shift public conversation quickly by putting a face and a personal story to what might otherwise stay an abstract statistic. NGOs and international bodies shape perspectives more gradually but often more durably, through repeated, evidence-based reporting (the IPCC's assessment reports are the clearest example) that sets the baseline facts institutions and media outlets then draw on. Educational institutions shape the next generation's perspective directly through curricula like this one, while social media has become a distinct and powerful channel of its own, capable of spreading both accurate climate science and misinformation at similar speed, which is part of why media literacy is now treated as a climate-relevant skill.
Why perspectives on urgency vary so widely
Perspectives on the necessity, practicality and urgency of climate action vary between individuals and between societies, particularly between age groups, developed and developing societies, coastal and inland communities, and economies that profit from fossil fuels versus those that do not. Age-based differences often trace to differing time horizons: a young person alive in 2100 has a direct stake in decisions made now in a way an older policymaker may not share, which is part of why youth-led climate movements have grown into a distinct political force over the past decade. Geography matters just as directly: a low-lying island state or a coastal delta community treats sea-level rise as an immediate, existential concern, while an inland, higher-elevation community may experience climate change mainly through slower-moving impacts such as shifting growing seasons, so urgency is not just a matter of belief but of different lived exposure to risk. Economic dependence shapes urgency too: a worker or region whose livelihood depends on coal mining or oil extraction faces a real, immediate cost from rapid decarbonization even if they accept the long-term science, which helps explain why climate policy is often as contested within countries as between them.
The tragedy of the commons
The tragedy of the commons suggests catastrophic climate change is likely unless there is international cooperation on an unprecedented scale. The atmosphere is common to all: when one nation benefits from an action that harms it, such as burning fossil fuels, the costs are shared by all nations and their ecosystems. The reverse is also true: the costs of restoring the atmosphere, for example through carbon capture and storage, might be borne by a single nation, while the benefits are gained by all.
The tragedy of the commons is introduced generally, with the classic shared-pasture example, on 1.3. This statement is that same concept applied specifically to the shared global atmosphere.
- COP30 Belem outcomes: UN News; Carbon Brief; World Resources Institute, November-December 2025.
- Kigali Amendment: UNEP Ozone Secretariat.
- IPCC Shared Socioeconomic Pathways (SSPs): IPCC Sixth Assessment Report (AR6).
- IB Environmental Systems and Societies Guide, first assessment 2026, Topic 6, Subtopic 6.3, statements 6.3.6-6.3.14.