The sources behind the columns

Several independent groups, using different methods and different data, all find the same warming: about 1.2 to 1.3 °C above the late nineteenth century. Models published in the 1970s and 1980s projected warming close to what was later measured.

1. GISTEMP global temperature, NASA GISS. How far each month and year sits above the long-term average. Data data.giss.nasa.gov named in 9 columns
2. HadCRUT temperature record, Climatic Research Unit. The UK global temperature record, kept with the Met Office. Data uea.ac.uk named in 4 columns
3. Berkeley Earth temperature, Berkeley Earth. An independent reconstruction of land and ocean temperature, built to test the others. Data berkeleyearth.org named in 12 columns
4. Copernicus Climate Change Service, ECMWF for the European Union. Monthly European temperature and reanalysis bulletins, the ERA5 record. Data climate.copernicus.eu
5. Climate at a Glance, NOAA NCEI. Temperature and rainfall history for any US state, county or city. Data ncei.noaa.gov
6. Earth System Grid Federation, ESGF. Where the climate model output itself is published. Data esgf.llnl.gov
7. IPCC Sixth Assessment: The Physical Science Basis, IPCC · 2021. What is known about how and why the climate is changing. Assessment ipcc.ch
8. World Meteorological Organization, WMO. The annual State of the Global Climate, and the greenhouse gas bulletin. Agency wmo.int named in 7 columns
9. Vital Signs of the Planet, NASA. The headline measurements, plainly presented. Data science.nasa.gov
10. World Climate Research Programme, WCRP. The body that coordinates CMIP, the model comparisons the IPCC rests on. Research wcrp-climate.org
11. RealClimate, Working climate scientists. Climate science explained by the people who do it. Research realclimate.org named in 2 columns
12. National Academies Press, US National Academies. Reports from the National Academies, free to read online. Research nap.nationalacademies.org named in 11 columns

Carbon dioxide in the air has climbed from about 315 parts per million when measurements began at Mauna Loa in 1958 to more than 420 today. Land and ocean absorb roughly half of what people emit each year; the rest accumulates.

1. Carbon dioxide at Mauna Loa, NOAA. The monthly CO₂ record from Hawaii, unbroken since 1958. Data gml.noaa.gov named in 11 columns
2. The Keeling Curve, Scripps Institution of Oceanography. The original daily CO₂ record begun by Charles David Keeling in 1958. Data keelingcurve.ucsd.edu named in 6 columns
3. Our World in Data: CO₂ and energy, Global Change Data Lab. Emissions and energy by country and year, charted and downloadable. Data ourworldindata.org named in 2 columns
4. CDIAC archive, ESS-DIVE. Historical emissions and greenhouse gas data sets from the former Oak Ridge center. Data cdiac.ess-dive.lbl.gov
5. Methane in the air, NOAA. The global methane record from the same flask network as the CO₂ curve. Data gml.noaa.gov
6. The Global Carbon Budget, Global Carbon Project. The annual accounting of where carbon came from and where it went. Research globalcarbonbudget.org
7. Ocean carbon and acidification data, NOAA PMEL. The moorings and cruises behind those numbers. Data pmel.noaa.gov
8. IPCC Sixth Assessment: The Physical Science Basis, IPCC · 2021. What is known about how and why the climate is changing. Assessment ipcc.ch
9. The Global Carbon Budget, Global Carbon Project. The annual accounting of where carbon came from and where it went. Research globalcarbonbudget.org
10. U.S. Greenhouse Gas Inventory, EPA. The official yearly count of US emissions, by gas and by sector. Agency epa.gov
11. World Meteorological Organization, WMO. The annual State of the Global Climate, and the greenhouse gas bulletin. Agency wmo.int named in 7 columns
12. International Energy Agency, Paris. Tracks global energy markets and the energy transition. Agency iea.org named in 15 columns
13. IPCC Sixth Assessment: Mitigation of Climate Change, IPCC. What it would take to stop making it worse. Assessment ipcc.ch
14. Project Drawdown, Project Drawdown. Solutions ranked by how much carbon each would actually avoid. Research drawdown.org named in 4 columns

Coal, oil and natural gas supply most of the world's energy and most of its carbon dioxide, and the arithmetic of replacing them is the central problem.

1. U.S. Energy Information Administration, US Department of Energy. Official US energy statistics: production, consumption and prices. Agency eia.gov named in 24 columns
2. Our World in Data: CO₂ and energy, Global Change Data Lab. Emissions and energy by country and year, charted and downloadable. Data ourworldindata.org named in 2 columns
3. International Energy Agency, Paris. Tracks global energy markets and the energy transition. Agency iea.org named in 15 columns
4. The Global Carbon Budget, Global Carbon Project. The annual accounting of where carbon came from and where it went. Research globalcarbonbudget.org
5. IPCC Sixth Assessment: Mitigation of Climate Change, IPCC. What it would take to stop making it worse. Assessment ipcc.ch

Arctic sea ice in September has lost roughly half its 1979 extent, and Greenland and Antarctica are together losing hundreds of billions of tonnes of ice a year.

1. Arctic Sea Ice News, NSIDC. Daily sea-ice extent, with a monthly analysis. Data nsidc.org named in 11 columns
2. Arctic Report Card, NOAA. The yearly check-up on Arctic ice, snow, permafrost and ocean. Data arctic.noaa.gov
3. GRACE-FO: ice and groundwater from orbit, NASA and GFZ. Twin satellites that weigh ice sheets and aquifers by measuring gravity. Data grace.jpl.nasa.gov named in 5 columns
4. Greenland ice sheet monitoring, GEUS, Denmark. The measurement network on the ice itself. Data promice.dk
5. IPCC Special Report on the Ocean and Cryosphere, IPCC · 2019. Oceans, ice and sea level in a changing climate. Assessment ipcc.ch
6. Arctic Monitoring and Assessment Programme, Arctic Council. Scientific assessments of the Arctic environment. Research amap.no
7. National Snow and Ice Data Center, NSIDC. Sea ice, glaciers, permafrost and snow. Agency nsidc.org named in 7 columns
8. British Antarctic Survey, BAS. Antarctic ice, ocean and ice-core research. Research bas.ac.uk

Global sea level has risen about 21 to 24 centimetres since 1880, and the rate has more than doubled since the early 1990s.

1. Sea level, NASA. Satellite measurements of global sea level since 1993. Data sealevel.nasa.gov
2. Sea level trends, NOAA Tides & Currents. Long-term sea level change at tide gauges on every US coast. Data tidesandcurrents.noaa.gov
3. GRACE-FO: ice and groundwater from orbit, NASA and GFZ. Twin satellites that weigh ice sheets and aquifers by measuring gravity. Data grace.jpl.nasa.gov named in 5 columns
4. IPCC Special Report on the Ocean and Cryosphere, IPCC · 2019. Oceans, ice and sea level in a changing climate. Assessment ipcc.ch
5. Fifth National Climate Assessment, USGCRP · 2023. Climate change in the United States, region by region, including the Northeast. NOAA Central Library copy. Assessment repository.library.noaa.gov
6. Climate Central, Climate Central. Attribution and local-impact tools built for the public. Research climatecentral.org named in 27 columns

A warmer atmosphere holds more water and more energy, which shows up as heavier rain, longer droughts, bigger fires and hotter heat waves.

1. Billion-dollar disasters, NOAA NCEI. Every U.S. weather disaster costing a billion dollars or more, since 1980. Data ncei.noaa.gov named in 10 columns
2. U.S. Drought Monitor, University of Nebraska–Lincoln. The weekly map of drought across the United States. Data droughtmonitor.unl.edu
3. Wildfire statistics, National Interagency Fire Center. Acres burned and fires counted, year by year. Data nifc.gov
4. National Hurricane Center, NOAA. Forecasts, and the archive of every storm. Data nhc.noaa.gov
5. IPCC Sixth Assessment: The Physical Science Basis, IPCC · 2021. What is known about how and why the climate is changing. Assessment ipcc.ch
6. Climate Central, Climate Central. Attribution and local-impact tools built for the public. Research climatecentral.org named in 27 columns
7. Fifth National Climate Assessment, USGCRP · 2023. Climate change in the United States, region by region, including the Northeast. NOAA Central Library copy. Assessment repository.library.noaa.gov

The ocean has absorbed more than ninety percent of the extra heat, which is why ocean heat content is the steadiest measure of the whole problem.

1. Global ocean heat content, NOAA NCEI. Where most of the extra energy actually goes. Data ncei.noaa.gov named in 2 columns
2. The Argo float array, UC San Diego and partners. Four thousand drifting floats measuring the upper ocean continuously. Data argo.ucsd.edu named in 10 columns
3. Coral Reef Watch, NOAA. Satellite bleaching alerts, reef by reef. Data coralreefwatch.noaa.gov
4. Ocean carbon and acidification data, NOAA PMEL. The moorings and cruises behind those numbers. Data pmel.noaa.gov
5. IPCC Special Report on the Ocean and Cryosphere, IPCC · 2019. Oceans, ice and sea level in a changing climate. Assessment ipcc.ch
6. Ocean Acidification Program, NOAA. What the extra CO₂ is doing to seawater chemistry. Agency oceanacidification.noaa.gov
7. Woods Hole Oceanographic Institution, WHOI. Ocean circulation, including the AMOC work. Research whoi.edu named in 6 columns

Forests absorb roughly a quarter of the carbon dioxide people emit, and what happens to them — growth, fire, disease, clearing — changes that number.

1. Forest Inventory and Analysis, USDA Forest Service. The running census of American forests, plot by plot. Moved to the Forest Service research site; fia.fs.usda.gov no longer resolves. Data research.fs.usda.gov
2. U.S. Forest Service, USDA. Forest health, fire and management research. Agency fs.usda.gov
3. Food and Agriculture Organization, United Nations. Global crop, land and food statistics. Agency fao.org
4. IPCC Sixth Assessment: The Physical Science Basis, IPCC · 2021. What is known about how and why the climate is changing. Assessment ipcc.ch
5. The Global Carbon Budget, Global Carbon Project. The annual accounting of where carbon came from and where it went. Research globalcarbonbudget.org

Plants and animals are shifting poleward and uphill as conditions move beneath them, and some have nowhere left to go.

1. The IUCN Red List, IUCN. Which species are in trouble, and how much. Data iucnredlist.org
2. Biodiversity and ecosystem assessments, IPBES. The biodiversity equivalent of the IPCC. Assessment ipbes.net
3. IPCC Sixth Assessment: Impacts, Adaptation and Vulnerability, IPCC. What the warming does, and what can be done about it. Assessment ipcc.ch
4. Food and Agriculture Organization, United Nations. Global crop, land and food statistics. Agency fao.org

Heat is the deadliest weather hazard in the United States, and the same combustion that warms the planet also fills the air with what people breathe.

1. Climate Change Indicators, EPA. Around fifty measured American indicators — temperature, drought, coastal flooding, glaciers. Removed from the EPA site in December 2025; this is an archived copy. Data web.archive.org removed December 2025 · archived copy named in 2 columns
2. The Lancet Countdown, The Lancet. Annual indicators on climate and human health. Research lancetcountdown.org
3. Climate change and health, World Health Organization. Heat, disease and air quality, globally. Agency who.int named in 2 columns
4. IPCC Sixth Assessment: Impacts, Adaptation and Vulnerability, IPCC. What the warming does, and what can be done about it. Assessment ipcc.ch

Growing seasons are lengthening and hardiness zones are shifting north, while heat and drought cut yields in the places least able to absorb the loss.

1. National water data, USGS. Streamflow and groundwater at tens of thousands of gauges. Data waterdata.usgs.gov
2. USDA Climate Hubs, USDA. Regional guidance written for farmers and foresters. Agency climatehubs.usda.gov
3. Food and Agriculture Organization, United Nations. Global crop, land and food statistics. Agency fao.org
4. IPCC Sixth Assessment: Impacts, Adaptation and Vulnerability, IPCC. What the warming does, and what can be done about it. Assessment ipcc.ch

Where the snow falls, when it melts and how much reaches the reservoir are changing faster than the systems built around them.

1. National water data, USGS. Streamflow and groundwater at tens of thousands of gauges. Data waterdata.usgs.gov
2. U.S. Drought Monitor, University of Nebraska–Lincoln. The weekly map of drought across the United States. Data droughtmonitor.unl.edu
3. U.S. Geological Survey, USGS. Land, water, ice and hazards. Agency usgs.gov named in 7 columns
4. IPCC Sixth Assessment: Impacts, Adaptation and Vulnerability, IPCC. What the warming does, and what can be done about it. Assessment ipcc.ch
5. Fifth National Climate Assessment, USGCRP · 2023. Climate change in the United States, region by region, including the Northeast. NOAA Central Library copy. Assessment repository.library.noaa.gov

Northern New York is warming faster in winter than in summer, which changes ice cover, snowpack, maple sugaring and the lake itself.

1. Lake Champlain Basin Program, LCBP. Water quality, ice cover and the State of the Lake reports. Data lcbp.org
2. Climate at a Glance, NOAA NCEI. Temperature and rainfall history for any US state, county or city. Data ncei.noaa.gov
3. The New York grid, hour by hour, NYISO. Who is generating what across the state, in real time. Data nyiso.com
4. New York State Climate Impacts Assessment, NYSERDA · 2024. What a changing climate means for New York's farms, water, health and communities. Assessment nysclimateimpacts.org
5. New York's Climate Act, New York State. The 2019 law, the scoping plan, and progress against it. Agency climate.ny.gov named in 13 columns
6. Department of Environmental Conservation, New York State. State monitoring, regulation and regional reporting. Agency dec.ny.gov
7. Ausable River Association, AsRA. Stream temperature, road salt and flood work in our own watershed. Research ausableriver.org
8. Adirondack Watershed Institute, Paul Smith's College. Lake and stream science across the Adirondack Park. Research adkwatershed.org
9. NYSERDA, New York State. State energy programmes, incentives and data. Agency nyserda.ny.gov

The cheapest and cleanest unit of energy is the one never used, which is why efficiency appears in almost every column Ray writes.

1. ENERGY STAR, EPA and DOE. What an efficient appliance or house actually is, defined and measured. Agency energystar.gov
2. U.S. Energy Information Administration, US Department of Energy. Official US energy statistics: production, consumption and prices. Agency eia.gov named in 24 columns
3. Energy Efficiency and Renewable Energy, U.S. Department of Energy. Programme data, standards, and the research behind them. Agency energy.gov
4. National Laboratory of the Rockies (formerly NREL), U.S. Department of Energy. Cost benchmarks, resource maps and technical baselines. Renamed from the National Renewable Energy Laboratory by the Department of Energy in 2025; nrel.gov no longer resolves. Agency nlr.gov named in 6 columns
5. RMI, RMI. Energy transition analysis, formerly the Rocky Mountain Institute. Research rmi.org named in 150 columns
6. Project Drawdown, Project Drawdown. Solutions ranked by how much carbon each would actually avoid. Research drawdown.org named in 4 columns

The price of a solar module has fallen by more than 99 percent since the 1970s, and solar is now the cheapest new electricity in much of the world.

1. Renewable energy statistics, IRENA. Renewable capacity and costs worldwide, from the International Renewable Energy Agency. Data irena.org named in 2 columns
2. Electric Power Monthly, EIA. Where US solar, wind, coal and gas generation are counted, month by month. Data eia.gov
3. Utility-scale solar, wind and storage reports, Lawrence Berkeley National Laboratory. The annual cost and performance reports the industry quotes. Research emp.lbl.gov
4. National Laboratory of the Rockies (formerly NREL), U.S. Department of Energy. Cost benchmarks, resource maps and technical baselines. Renamed from the National Renewable Energy Laboratory by the Department of Energy in 2025; nrel.gov no longer resolves. Agency nlr.gov named in 6 columns
5. Global Electricity Review, Ember. What the world's power stations actually generated, by fuel. Research ember-energy.org named in 114 columns
6. PV Magazine, Energy news. Solar industry news and market figures. News pv-magazine.com named in 3 columns
7. PV Tech, Energy news. Solar project and manufacturing news. News pv-tech.org

Turbines have grown from 50-kilowatt machines to 15-megawatt offshore giants, and wind now supplies about a tenth of American electricity.

1. Renewable energy statistics, IRENA. Renewable capacity and costs worldwide, from the International Renewable Energy Agency. Data irena.org named in 2 columns
2. Electric Power Monthly, EIA. Where US solar, wind, coal and gas generation are counted, month by month. Data eia.gov
3. Utility-scale solar, wind and storage reports, Lawrence Berkeley National Laboratory. The annual cost and performance reports the industry quotes. Research emp.lbl.gov
4. American Clean Power Association, Industry. US wind, solar and storage installation data. Research cleanpower.org
5. National Laboratory of the Rockies (formerly NREL), U.S. Department of Energy. Cost benchmarks, resource maps and technical baselines. Renamed from the National Renewable Energy Laboratory by the Department of Energy in 2025; nrel.gov no longer resolves. Agency nlr.gov named in 6 columns
6. Global Electricity Review, Ember. What the world's power stations actually generated, by fuel. Research ember-energy.org named in 114 columns

Nuclear plants supply about a fifth of American electricity with almost no carbon dioxide, and the argument is about cost, waste and time.

1. Electric Power Monthly, EIA. Where US solar, wind, coal and gas generation are counted, month by month. Data eia.gov
2. International Energy Agency, Paris. Tracks global energy markets and the energy transition. Agency iea.org named in 15 columns
3. National Laboratory of the Rockies (formerly NREL), U.S. Department of Energy. Cost benchmarks, resource maps and technical baselines. Renamed from the National Renewable Energy Laboratory by the Department of Energy in 2025; nrel.gov no longer resolves. Agency nlr.gov named in 6 columns
4. IPCC Sixth Assessment: Mitigation of Climate Change, IPCC. What it would take to stop making it worse. Assessment ipcc.ch

Lithium battery costs have fallen roughly 90 percent since 2010, which is what made both electric cars and grid storage ordinary.

1. Electric Power Monthly, EIA. Where US solar, wind, coal and gas generation are counted, month by month. Data eia.gov
2. Utility-scale solar, wind and storage reports, Lawrence Berkeley National Laboratory. The annual cost and performance reports the industry quotes. Research emp.lbl.gov
3. National Laboratory of the Rockies (formerly NREL), U.S. Department of Energy. Cost benchmarks, resource maps and technical baselines. Renamed from the National Renewable Energy Laboratory by the Department of Energy in 2025; nrel.gov no longer resolves. Agency nlr.gov named in 6 columns
4. BloombergNEF, Bloomberg. Research on energy-transition markets and investment. Research about.bnef.com named in 6 columns
5. RMI, RMI. Energy transition analysis, formerly the Rocky Mountain Institute. Research rmi.org named in 150 columns

The hard part of a renewable grid is not generating the electricity but moving it and matching it to demand, hour by hour.

1. The New York grid, hour by hour, NYISO. Who is generating what across the state, in real time. Data nyiso.com
2. Electric Power Monthly, EIA. Where US solar, wind, coal and gas generation are counted, month by month. Data eia.gov
3. Federal Energy Regulatory Commission, FERC. Interconnection queues, transmission, wholesale markets. Agency ferc.gov named in 3 columns
4. Reliability assessments, North American Electric Reliability Corporation. Whether the grid can meet demand, season by season. Research nerc.com
5. National Laboratory of the Rockies (formerly NREL), U.S. Department of Energy. Cost benchmarks, resource maps and technical baselines. Renamed from the National Renewable Energy Laboratory by the Department of Energy in 2025; nrel.gov no longer resolves. Agency nlr.gov named in 6 columns
6. Global Electricity Review, Ember. What the world's power stations actually generated, by fuel. Research ember-energy.org named in 114 columns

An electric car emits less over its life than a fossil-fuel-powered one on any grid in the United States, and the gap widens as the grid cleans up.

1. U.S. Energy Information Administration, US Department of Energy. Official US energy statistics: production, consumption and prices. Agency eia.gov named in 24 columns
2. International Energy Agency, Paris. Tracks global energy markets and the energy transition. Agency iea.org named in 15 columns
3. National Laboratory of the Rockies (formerly NREL), U.S. Department of Energy. Cost benchmarks, resource maps and technical baselines. Renamed from the National Renewable Energy Laboratory by the Department of Energy in 2025; nrel.gov no longer resolves. Agency nlr.gov named in 6 columns
4. CleanTechnica, Energy news. Daily news on electric vehicles, solar, wind and storage. News cleantechnica.com named in 32 columns

Hydrogen is a way of carrying energy, not a source of it, and it is worth the losses only where nothing else works: steel, shipping, fertiliser.

1. The Hydrogen Program, U.S. Department of Energy. Costs, methods and the hubs programme. Agency hydrogen.energy.gov
2. International Energy Agency, Paris. Tracks global energy markets and the energy transition. Agency iea.org named in 15 columns
3. National Laboratory of the Rockies (formerly NREL), U.S. Department of Energy. Cost benchmarks, resource maps and technical baselines. Renamed from the National Renewable Energy Laboratory by the Department of Energy in 2025; nrel.gov no longer resolves. Agency nlr.gov named in 6 columns

For most of the world the cheapest new power plant is now wind or solar, so the costs being argued over are those of damage and delay. The Paris Agreement asks every country to say what it will do and come back with more; the argument is whether the sum is enough.

1. U.S. Energy Information Administration, US Department of Energy. Official US energy statistics: production, consumption and prices. Agency eia.gov named in 24 columns
2. Our World in Data: CO₂ and energy, Global Change Data Lab. Emissions and energy by country and year, charted and downloadable. Data ourworldindata.org named in 2 columns
3. Billion-dollar disasters, NOAA NCEI. Every U.S. weather disaster costing a billion dollars or more, since 1980. Data ncei.noaa.gov named in 10 columns
4. International Energy Agency, Paris. Tracks global energy markets and the energy transition. Agency iea.org named in 15 columns
5. BloombergNEF, Bloomberg. Research on energy-transition markets and investment. Research about.bnef.com named in 6 columns
6. RMI, RMI. Energy transition analysis, formerly the Rocky Mountain Institute. Research rmi.org named in 150 columns
7. IPCC Sixth Assessment: Mitigation of Climate Change, IPCC. What it would take to stop making it worse. Assessment ipcc.ch
8. UN Environment Programme, UNEP. The Emissions Gap and Adaptation Gap reports. Agency unep.org
9. Sabin Center for Climate Change Law, Columbia Law School. Databases of climate law and litigation. Research climate.law.columbia.edu
10. New York's Climate Act, New York State. The 2019 law, the scoping plan, and progress against it. Agency climate.ny.gov named in 13 columns

New York now requires climate education in its schools, and the Essential Principles of Climate Literacy — eight of them, in the 2024 third edition — are the frame most of that teaching uses.

1. Essential Principles of Climate Literacy, NOAA and USGCRP. The seven principles most climate teaching is built on. Assessment climate.gov
2. The CLEAN teaching collection, Climate Literacy and Energy Awareness Network. Reviewed classroom materials, by grade and topic. Research cleanet.org
3. NOAA Education, NOAA. Lessons, data activities and teacher resources. Agency noaa.gov
4. MetEd, UCAR. Free training modules on weather and climate. Research meted.ucar.edu

The scientific agreement has been measured repeatedly and sits above 97 percent; the public impression is not in line with that.

1. Skeptical Science, Skeptical Science. Each common objection, with the published answer. Research skepticalscience.com
2. RealClimate, Working climate scientists. Climate science explained by the people who do it. Research realclimate.org named in 2 columns
3. Carbon Brief, Carbon Brief. Science and policy explained carefully, with the papers linked. News carbonbrief.org named in 3 columns
4. Yale Climate Connections, Yale University. Daily reporting and radio pieces for a general audience. News yaleclimateconnections.org named in 2 columns