This article documents events, research findings, effects, and responses related to global warming and climate change during the year 2023.

Summaries

• 20 March – The final synthesis of the IPCC Sixth Assessment Report is published. It summarises the state of knowledge relating to climate change with assessed levels of confidence. Conclusions in the summary for contemporary policy-makers include that the extent to which both current and future generations will be impacted depends on choices now and in the near-term, with "high confidence" that policies implemented by the end of 2020 are "projected to result in higher global GHG emissions in 2030 than emissions implied by NDCs" and would fail to meet global climate goals.^[2]

Measurements and statistics

• 3 January: the National Snow and Ice Data Center reported that Antarctic sea ice extent stood at the lowest in the 45-year satellite record—more than 500,000 square kilometers (193,000 square miles) below the previous record (2018), with four of the five lowest years for the last half of December having occurred since 2016.^[3]
• 26 January: Bloomberg NEF's "Energy Transition Investment Trends" report estimated that, for the first time, energy transition investment matched global fossil fuel investment—$1.1 trillion in 2022, including China with $546 billion, the US with $141 billion, and the EU if treated as a bloc, $180 billion.^[4]
• Reported 10 May: Drax Electric Insights reported that in the first three months of 2023, Britain's wind turbines generated more electricity (32.4%) than gas-fired power stations (31.7%) for the first time.^[5]
• 18 May: a study published in Science reported that more than 50% of freshwater lakes and reservoirs lost volume from 1992 to 2020.^[6]

Natural events and phenomena

• 7 February: a study published in Nature Communications concluded that 15 million people globally are exposed to impacts from potential glacial lake outburst floods (GLOFs), more than half being from India, Pakistan, Peru, and China.^[7] Climate change has intensified glacial ice melt and expanded glacial lakes.^[7]
• 13 February: a study published in the Proceedings of the National Academy of Sciences reported that increasing abundance of a thermotolerant symbiotic alga hosted by corals has facilitated maintenance of high coral cover after three mass coral bleaching events, suggesting that future reefs might maintain high cover for several decades, albeit with low diversity and provided that other stressors are minimized.^[8]
• 2 March: a study published in Science said that boreal fires, typically accounting for 10% of global fire CO₂ emissions, contributed 23% in 2021, by far the highest fraction since 2000.^[9] 2021 was an abnormal year because North American and Eurasian boreal forests synchronously experienced their greatest water deficit.^[9]
• 13 March: a study published in Nature Water found that total intensity of extreme events (droughts and pluvials (rainfall events)) is strongly correlated with global mean temperature, and concluded that continued warming of the planet will cause more frequent, more severe, longer and/or larger of such extreme events, and that "distortion of the water cycle... will be among the most conspicuous consequences of climate change".^[10]
• 15 February: Two joint studies by the British Antarctic Survey and the US Antarctic programme finds that glaciers on the icy continent may be more sensitive to changes in sea temperature than previously thought. Researchers used sensors and an underwater robot beneath the Thwaites glacier to study melting.^[11][12][13] One day earlier, a new record low Antarctic sea ice extent is reported by the National Snow and Ice Data Center in the US, beating the previous record set a year earlier.^[14][15]
• 7 April: citing reduced air density caused by global warming, a study published in the Bulletin of the American Meteorological Society estimated global warming has enabled more than 500 excess home runs in Major League Baseball since 2010, and projected hundreds more in this century, explaining that "even the elite billion-dollar sports industry is vulnerable to unexpected impacts" of global warming.^[16]
• 29 March: a study published in Nature concluded that under a high-emissions scenario, abyssal warming is set to accelerate over the next 30 years, and that meltwater input around Antarctica drives a contraction of Antarctic Bottom Water (AABW), opening a pathway that allows warm circumpolar deep water greater access to the continental shelf and results in warming and aging of the abyssal ocean.^[17] The study described the "critical importance of Antarctic meltwater in setting the abyssal ocean overturning, with implications for global ocean biogeochemistry and climate that could last for centuries".^[17]

Actions, and goal statements

Science and technology

• Progress in climate change mitigation implementation research:
  • 5 January: A paywalled meta-analysis in Nature Climate Change reports "required technology-level investment shifts for climate-relevant infrastructure until 2035" within the EU, which it finds to be "most drastic for power plants, electricity grids and rail infrastructure", ~87€ billion above the planned budgets and in need of sustainable finance policies.^[18][19]
  • 12 January: A study in Environmental Research Letters suggests that applying the principle of extended producer responsibility to fossil fuels could deconflict energy security and climate policy at an affordable cost, in particular authors suggest the responsibility could be used to establish the financing of CO₂ storage and nature-based solutions.^[20][21]
  • 30 January: A study in Nature Sustainability outlines challenges of aviation decarbonization by 2050 whose identified factors mainly are future demand, continuous efficiency improvements, new short-haul engines, higher SAF (biofuel) production, CO₂ removal to compensate for non-CO₂ forcing, and related policy-options. With constant air transport demand and aircraft efficiency, decarbonizing aviation would require nearly five times the 2019 worldwide biofuel production, competing with other hard-to-decarbonize sectors and land-use (or food security). As of 2023, fuel represents 20-30% of the airlines' operating costs, while SAF is 2–4 times more expensive than fossil jet fuel.^[22]
  • 6 February: A study in Nature Climate Change integrates policy as an aspect into an integrated assessment model, showing that Powering Past Coal Alliance-based (from COP23) coal phase-out is highly unlikely (<5%) with current policies where both coal-use would substantially only shift from power to other industries (steel, cement, and chemicals) and China will now potentially "dangerously delay" the phase-out.^[23][24]
  • 8 February: Scientists in the U.S. propose mining the lunar soil and launching it towards the Sun to form a shield (space sunshade) against global warming.^[25][26]
  • 19 February: A study in Ethics, Policy & Environment reports that rationing has been neglected as a policy option for mitigating climate change, and, partly based on historical data and economic analysis, concludes that such personal carbon allowances (PCAs) could help states reduce emissions rapidly and fairly. It suggests built-in fair shares mechanisms would be a key part of two-currency PCA economics and that carbon taxes-only economics would not have effects that are as quick and equitable, with their fairness issues potentially including disproportionate impacts on low-income populations (or intensified economic inequality in general). There could be 'carbon cards' for all-encompassing CAs (e.g. using life-cycle assessment for supermarket items [as in 8 Aug 22]) or per-capita rationing of (scientifically) selected goods such as meat, flights, and/or fossil fuels to adapt to the scarce (physically limited) carbon budget available to meet goals. PCAs could also help address other issues such as the energy crisis and viably accelerate sustainability transitions of domains ranging from lifestyles to investments but may require smaller initial steps than an entire-population-national rationing implementation.^[27][28]
  • 3 March: After a study (31 Jan) indicated that in building heating in the EU, the feasibility of staying within planetary boundaries is possible only through electrification, with green hydrogen heating being 2–3 times more expensive than heat pump costs,^[29][30] a study indicates that replacing gas boilers with heat pumps is the fastest way to cut German gas consumption.^[31]

Political, economic, legal, and cultural actions

• 1 January: Extinction Rebellion made a statement that for 2023 it had made "a controversial resolution to temporarily shift away from public disruption as a primary tactic", after 2022's traffic blockages and throwing soup on the case of Vincent van Gogh’s "Sunflowers" painting.^[32]
• 11 January: the French National Assembly adopted the Acceleration of Renewable Energies bill, which includes a requirement to install solar panels on all car parks (parking lots) of over 1,500 square metres (16,100 square feet).^[33]
• 25 January: A paper in Harvard Environmental Law Review suggests that according to already-existing law fossil fuel companies may be chargeable with homicide due to climate change effects and e.g. partly their deception of the public and proactive prevention of regulations or adequate regulations. The paper is focused on corporate actors and does not address e.g. politicians' and policymakers' responsibilities, economic pressures or incentives, and responsibilities for solutions to these underlying economic issues.^[34][35]
• 14 February: the European Parliament effectively banned sale of new petrol and diesel cars in the European Union from 2035, and set a 55% cut over 2021 CO₂ emission levels for new cars sold from 2030.^[36]
• March: the UN 2023 Water Conference was held in New York.^[37]
• 21 April: a review study published in One Earth stated that opinion polls show that most people perceive climate change as occurring now and close by.^[38] The study concluded that seeing climate change as more distant does not necessarily result in less climate action, and reducing psychological distancing does not reliably increase climate action.^[38]
• 21 April: the Director General of the United Nations' International Organization for Migration said that there are more people displaced because of climate change than because of conflicts, explaining that climate change and conflict interact as triggers of displacement.^[39]
• 19 May: a study published in One Earth estimated that the top 21 fossil fuel companies will owe cumulative climate reparations of $5.4 trillion over the period 2025–2050.^[40]
• November: the 2023 United Nations Climate Change Conference is scheduled to be held in Dubai.^[41]

Mitigation goal statements

• 15 April: a communique from a meeting of G7 ministers pledged to collectively increase offshore wind capacity by 150 gigawatts by 2030 and solar capacity to more than 1 terawatt, and agreed to accelerate the phase-out of unabated (without recapture) fossil fuels to achieve net zero by 2050.^[42] They stopped short of endorsing a 2030 deadline for phasing out coal, and left the door open for continued investment in gas to help address potential energy shortfalls.^[42]

Adaptation goal statements

Consensus

Projections

Projections for different amounts of global warming: Melting of glacial mass, sea level rise, and loss of number of glaciers.^[43]

• 2 January: a study published in Earth's Future (American Geophysical Union) concluded that the greatest increase in the amount of coastal area below mean sea level will occur in the early stages of sea level rise (SLR), contrary to earlier assessments, shortening time for adaptation efforts.^[45] Latest projections indicate that SLR is certain to exceed 2 metres (6.6 ft) in coming centuries, and a rise by 4 metres (13 ft) is considered possible.^[45]
• 5 January: a study published in Science stated that, based on then-current pledges, global mean temperature is projected to increase by +2.7 °C, which would cause loss of about half of Earth's glaciers by 2100, causing a sea level rise of 115±40 millimeters (not counting ice sheet melt).^[43]
• 30 January: Climate scientists predict, using artificial intelligence, in Proceedings of the National Academy of Sciences that global warming will exceed 1.5 °C in the next decade (scenario SSP2-4.5), and a nearly 70% chance of 2 °C between 2044 and 2065 (~2054) – a substantial probability of exceeding the 2 °C threshold – even if emissions rapidly decline (scenario SSP1-2.6).^[46][47]
• February: the International Energy Agency's Electricity Market Report 2023 projected that low-emissions sources will constitute almost all the growth in global electricity demand through 2025, with renewables' portion of global power generation rising from 29% in 2022 to 35% in 2025.^[48]
• 6 March: The highest-granularity study on food GHGs, published in Nature Climate Change, reports that global food consumption alone would lead to failed climate goals with constant patterns, with ~75% of the projected warming due to ruminant meat, dairy and rice, albeit consumption currently shifts towards higher emissions overall as economic development is expected to facilitate acquisitions of undifferentiated goods like beef.^[49][50]
• 13 March: a study published in Nature Sustainability forecast that floating photovoltaic (FPV) systems on reservoirs could provide 9,434±29 terawatt-hours/year^[51]—over a third of global electricity.^[52]
• 27 March: a study in Geophysical Research Letters attempts to provide estimations of the tipping point(s) of the Greenland ice sheet.^[53][54]
• 5 April: in its Boom and Bust Coal publication, Global Energy Monitor stated that phasing out operating coal power by 2040 would require an average of 117 GW of retirements per year—4.5 times the capacity retired in 2022.^[55] An average of 60 GW/yr for OECD countries, and 91 GW/year for non-OECD countries, must come offline.^[55]
• 17 May: the WMO Global Annual to Decadal Climate Update projected that the chance of global near-surface temperature exceeding 1.5°C above preindustrial levels for at least one year between 2023 and 2027 is 66%, though it is unlikely (32%) that the five-year mean will exceed 1.5°C.^[56]
• 20 May: a study published in One Earth found that increased temperature delays sleep onset and increases the probability of insufficient sleep, estimating that global warming may erode 50–58 hours of sleep per person-year while producing geographic inequalities that scale with future emissions.^[57]
• 22 May: a study published in Nature Sustainability projected that current policies leading to ~2.7 °C global warming could leave 22–39% of humans outside their "human climate niche"—defined as "the historically highly conserved distribution of relative human population density with respect to mean annual temperature."^[58] The study projected that reducing warming from 2.7 to 1.5 °C would result in a ~5-fold decrease in population exposed to unprecedented heat.^[58]

Significant publications

• February: "Electricity Market Report 2023" (PDF). iea.org. International Energy Agency. February 2023. Archived (PDF) from the original on 9 February 2023.
• 22 March: "AR6 Synthesis Report / Headline Statements". IPCC.ch. Intergovernmental Panel on Climate Change. March 2023. Archived from the original on 22 March 2023.
• 22 March: "Longer Report of the Synthesis Report of the IPCC Six Assessment Report (AR6)" (PDF). IPCC.ch. Intergovernmental Panel on Climate Change. March 2023. Archived (PDF) from the original on 22 March 2023.
• 23 March: Gilmore, Anna B; et al. (April 2023). "Defining and conceptualising the commercial determinants of health". The Lancet. 401 (10383): 1194–1213. doi:10.1016/s0140-6736(23)00013-2. ISSN 0140-6736. PMID 36966782. S2CID 257698115.
• 21 April: "State of the Global Climate". WMO.int. World Meteorological Organization (WMO). 21 April 2023. Archived from the original on 21 April 2023.
• 17 May: "WMO Global Annual to Decadal Climate Update". World Meteorological Organization. 17 May 2023. Archived from the original on 17 May 2023.