Scientists have understood the science of climate change for a long time, with Eunice Newton Foote and John Tyndall describing the greenhouse effect in the 1850s and Svante Arrhenius calculating the impact of CO2 in 1896. What is new and urgent is the clear evidence of climate change that confirms scientists’ projections. In 2026, researchers observe this evidence in global temperature records, sea-level data, ice-core samples, extreme weather studies, and ecosystem changes worldwide. The IPCC Sixth Assessment Report, the World Meteorological Organization, and NASA provide key climate change facts. These facts are essential for anyone engaged in sustainability. They are also crucial for the environment or responsible business practices in 2026.
Summary
- 2024 was confirmed as the first calendar year where the global average temperature exceeded 1.5°C above the pre-industrial baseline (World Meteorological Organisation).
- The IPCC AR6 states with unequivocal certainty that human activities are the primary cause of observed warming.
- Atmospheric CO2 exceeded 422 parts per million in 2024, the highest level in at least 3 million years of Earth’s history.
- The remaining carbon budget for a 50% chance of staying below 1.5°C was approximately 500 GtCO2 as of January 2020. At current emission rates, it runs out within 6-8 years.
- Every fraction of a degree of warming avoided translates into a measurable reduction in physical risk. Climate action at the margin is never wasted.
Fact 1: Is 1.5°C of Global Warming Already Here?
The Paris Agreement set 1.5°C above pre-industrial levels as the aspirational warming limit, beyond which climate risks escalate substantially. The IPCC AR6 Synthesis Report (2023) concluded that global surface temperatures will likely exceed 1.5°C during the 21st century under all considered emissions scenarios. Then came 2024. The World Meteorological Organisation confirmed it as the first calendar year in which the global average temperature exceeded 1.5°C above the pre-industrial baseline. That threshold crossing does not constitute a permanent exceedance under the climate treaty definition, which is based on multi-decade averages. But it is a profound signal of the trajectory underway. Keeping warming below 1.5°C requires global greenhouse gas emissions to peak before 2025 and decline 43% by 2030. That window is closing fast.
Fact 2: Are Humans Unequivocally the Cause of Climate Change?
Yes. The IPCC AR6 Working Group I report (2021) stated with unequivocal certainty, the highest confidence level in IPCC terminology, that human influence has warmed the atmosphere, ocean, and land. This warming is driven primarily by the combustion of fossil fuels such as coal, oil, and natural gas. Burning these fuels releases carbon dioxide and methane. These gases have been sequestered in geological formations over millions of years. Agriculture, deforestation, and industrial processes contribute additional greenhouse gas emissions. The atmospheric concentration of CO2 in 2024 exceeded 422 parts per million, the highest level in at least 3 million years of Earth’s history.
Fact 3: Is the Last Decade the Hottest on Record?
Each of the past five decades has been successively warmer than any preceding decade since instrumental records began. The period 2011 to 2020 was the warmest decade on record globally. In addition, 2023 was confirmed as the warmest year on record, approximately 1.45°C above the pre-industrial average. This warming is not uniformly distributed. The Arctic is warming approximately four times faster than the global average. This rapid warming has profound consequences for sea ice and permafrost stability. It also affects global ocean circulation patterns that regulate weather across the Northern Hemisphere.
Fact 4: How Fast Are Sea Levels Rising?
Since 1900, global mean sea level has risen approximately 20 cm. This rise is driven by thermal expansion of the oceans. It is also caused by the melting of glaciers and ice sheets. The rate of sea level rise more than doubled between 2006 and 2018, reaching approximately 3.7 mm per year. Under high-emissions scenarios, the IPCC projects global mean sea level rise of 0.63 to 1.01 m by 2100, with low-likelihood but higher-impact scenarios of up to 1.5 to 2 m if ice sheet instabilities are triggered. For the approximately 1 billion people living in low-elevation coastal zones, sea level rise is among the most consequential physical climate risks of this century.
Fact 5: Are Extreme Weather Events Getting Worse?
Climate attribution science, the field that assesses the contribution of climate change to specific extreme weather events, has advanced dramatically in the past decade. The evidence is now firm. Climate change has increased the frequency and intensity of heatwaves. It has also affected heavy precipitation events, droughts, and the most intense tropical cyclones. The economic costs are mounting rapidly. Munich Re estimated that weather-related insured losses exceeded $100 billion globally for the fifth consecutive year in 2023. For infrastructure planners, insurers, and risk managers, the core challenge is non-stationarity: historical weather data no longer reliably predict future hazard probabilities. The distribution has shifted.
Fact 6: What Is Happening to the Ocean?
The global ocean has absorbed more than 90% of the excess energy accumulated in the Earth system due to the enhanced greenhouse effect since 1970. This ocean heat uptake moderates surface warming. It drives the poleward migration of marine species. It also bleaches coral reefs and alters the productivity of fisheries. Billions of people depend on these fisheries for food and livelihoods. Simultaneously, the ocean absorbs approximately 25-30% of annual anthropogenic CO2 emissions, which react with seawater to form carbonic acid. Ocean pH has declined by approximately 0.1 units since the pre-industrial era. This decline represents a 26% increase in acidity. The increase has severe consequences for corals, molluscs, and the base of marine food webs.
Fact 7: How Much Carbon Budget Is Left?
A carbon budget is the total cumulative amount of CO2 that can be emitted while still limiting warming to a given temperature threshold with a specified probability. The IPCC AR6 estimated that, as of January 2020, the remaining carbon budget for a 50% probability of limiting warming to 1.5°C was approximately 500 GtCO2. At current global emission rates of approximately 40 GtCO2 per year, that budget runs out within approximately 6 to 8 years. The remaining budget for a 67% probability of limiting warming to 2°C is approximately 1,150 GtCO2 as of 2020. This equates to roughly 25-30 years at current rates. These figures make the required pace and scale of emissions reductions starkly clear. We are not on track.
Fact 8: Who Suffers Most from Climate Change?
The distribution of climate change impacts is profoundly inequitable. The countries and communities that have contributed least to cumulative greenhouse gas emissions face the most severe impacts. These include small island developing states, sub-Saharan Africa, and South and Southeast Asia. They endure sea level rise and storm surge, extreme heat stress, drought and water scarcity, and agricultural yield decline. The IPCC AR6 Working Group II report documents that approximately 3.3 to 3.6 billion people live in contexts highly vulnerable to climate change. Mortality from extreme heat, infectious diseases, and food insecurity is already elevated in climate-exposed regions. Climate justice is the principle that the burden of climate action and adaptation should be distributed equitably. This should be with respect to responsibility and vulnerability. It is now central to both climate negotiations. It’s also central to sustainability governance frameworks.
Fact 9: Do We Already Have the Solutions to Climate Change?
Yes, and this is the most important fact of all. The IPCC AR6 Working Group III report (2022) concluded that the technical and economic options for limiting global warming to 1.5°C or 2°C are available and, in many cases, cost-effective. Solar and wind energy are now the cheapest sources of new electricity generation in most of the world. Electric vehicle adoption is accelerating globally. Energy efficiency improvements are technically achievable across all sectors. The gap between current Nationally Determined Contribution (NDC) commitments under the Paris Agreement is significant. It remains large compared to the emissions reductions required to meet the 1.5°C target. Current policies are projected to result in approximately 2.5-3°C of warming by 2100. The barrier is not technological. It is political economy, investment allocation, and institutional inertia.
Fact 10: Does Every Fraction of a Degree Really Matter?
It matters enormously. Every tenth of a degree of warming avoided translates into meaningful reductions in physical risk: fewer people exposed to lethal heat stress, lower probability of coral reef collapse, reduced frequency of extreme precipitation events, and greater food system stability. The difference between 1.5°C and 2°C is not marginal. At 2°C, virtually all tropical coral reefs face long-term decline or functional collapse. At 1.5°C, 70 to 90% face severe pressure, but some survive. This non-linearity of climate risk implies ambition at the margin is always valuable. National policy, corporate strategy, and individual behaviour all play a role. The emissions we avoid today directly determine the physical world that future generations inherit. For a deeper look at what organisations can do, see our posts on ESG reporting frameworks and sustainability assessment methods.
Frequently Asked Questions: Climate Change in 2026
What is the IPCC and why should I trust its findings?
The Intergovernmental Panel on Climate Change (IPCC) is a UN body that assesses the scientific, technical, and socioeconomic information relevant to understanding human-induced climate change. It does not conduct original research. Instead, it synthesises and evaluates the peer-reviewed scientific literature, drawing on contributions from thousands of scientists worldwide. Its assessments go through multiple rounds of expert and government review before publication. The IPCC Sixth Assessment Report (AR6), completed in 2022-2023, represents the most comprehensive synthesis of climate science ever produced.
Has the 1.5°C target already been breached?
The year 2024 was confirmed as the first calendar year in which the global average surface temperature exceeded 1.5°C above the pre-industrial baseline. However, the Paris Agreement’s 1.5°C limit refers to long-term warming measured as a multi-decade average, not a single year. A single year above 1.5°C does not constitute a violation of the treaty. But it does confirm that the Earth system is moving rapidly toward and beyond this threshold, underscoring the urgency of deep, rapid emissions reductions.
What is a carbon budget?
A carbon budget is the total cumulative amount of CO2 that can be emitted into the atmosphere while still having a specified probability of limiting global warming to a given temperature threshold. The IPCC calculates remaining carbon budgets as a key tool for communicating how much further emissions must fall to meet climate targets. As of early 2026, the remaining budget for a 50% chance of limiting warming to 1.5°C is approximately 200-300 GtCO2, representing less than a decade of current global emissions.
What is climate attribution science?
Climate attribution science is the field that assesses the degree to which human-induced climate change has contributed to specific extreme weather events. Using climate models, statisticians compare the probability of an extreme event in a world with human greenhouse gas emissions versus a counterfactual world without them. This field has matured rapidly and is now capable of attributing individual events, such as specific heatwaves, floods, or droughts, to climate change with quantified confidence levels.
What can individuals and organisations do about climate change in 2026?
For individuals, the highest-impact actions include reducing aviation, shifting to a lower-meat diet, switching to renewable energy, and engaging in civic advocacy for stronger climate policy. For organisations, the priority is setting Science-Based Targets (SBTi) for Scope 1, 2, and 3 emissions, conducting credible sustainability assessments, and integrating climate risk disclosure into reporting frameworks, including CSRD and ISSB IFRS S2. Both levels of action are necessary. Systemic change requires credible individual and institutional commitment acting in parallel.
Related reading: Why Biodiversity Is the Backbone of a Stable Global Economy | GRI vs SASB vs TCFD vs ISSB: ESG Reporting Frameworks | Why Sustainability Assessment Matters | Air Pollution and Respiratory Health in Urban India
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