Earthward: State of the Climate

Greetings! Belated Happy New Year to all, and welcome back to Earthward for 2024. We said goodbye to 2023 on an optimistic note – an unprecedented pledge at the UN’s December COP28 meeting calling for a “transition away” from fossil fuel energy, and new leadership from the US and China that produced a resolution for member nations to reduce methane and other non-CO2 emissions. But the holiday season is also when analysts crunch the climate numbers for the prior year, and the message this time is hard to see in a positive light. In 2023 surface temperatures worldwide, and in many individual countries, exceeded all previous records by remarkably wide margins. Healthy climate advocates thus head into 2024 with elevated levels of urgency and, in some quarters, concern for whether climate models are really yielding trustworthy projections. Lets begin the year with a brief survey of the key findings as reported by US federal agencies (NOAA and NASA), an academic think tank (Berkeley Earth), the World Meteorological Organization (WMO), and numerous other groups – all ably synthesized by Zeke Hausfather at the invaluable climate journalism website CarbonBrief (see the first citation below).

The new data come as no surprise given reports this Fall on the extraordinary September heat wave, which topped the previous monthly record by nearly a full degree Fahrenheit (see Earthward, Oct. 19). Over all of 2023, average surface temperatures exceeded the previously warmest year, 2016, by about 0.15°C, and (depending on details of the analyses) closely approached or even topped the 1.5°C aspirational limit for anthropogenic warming. CarbonBrief’s synthesis emphasizes that the 1.5°C target is interpreted over a 20 year period, so a single year at that level does not mean we have crossed the line. Rather, most analyses presently attribute a value of 1.2 – 1.3°C to human-caused warming compared to preindustrial temperatures, with the 1.5°C limit still 6-10 years off.

The 2023 temperature spike is not well understood, but at least two factors seem likely to contribute: better pollution control leading to decreased atmospheric aerosols from fossil fuels (which have a cooling effect), and the beginning of a new El Nino climate pattern over the Pacific Ocean, a well-known natural climate variation that increases temperatures. The CarbonBrief synthesis incorporates all the major experimental temperature datasets, and concludes that 2023’s warming, while stronger than expected, is still broadly in line with the projections of climate models. This is the consensus message from the climate science community, but we would be remiss to skip over a contrary view promoted by Columbia University scientist Jim Hansen, whose independent analysis of last year’s data leads him to assert that the world has already reached 1.5°C of anthropogenic warming.

The basis for the disagreement has to do with how aerosol cooling is incorporated into the computer models. Dr. Hansen argues that most global climate models use an unrealistically small aerosol effect, thus producing less projected warming when aerosol levels are decreased. Hansen’s unquestioned expertise and past leadership at NASA, and his pathbreaking 1988 Congressional testimony and subsequent high public profile (elevated by attacks from climate change deniers) make his analyses highly influential with the public – although they are often criticized by other researchers as reflecting worst-case scenarios. Hansen, for his part, suggests that some in the climate science community resist his findings because of a natural tendency to take a conservative view. In other words, new findings that sharply challenge the status quo, as Hansen’s do, are not easily accepted. This is a common dynamic in virtually all scientific disciplines, but it resonates especially strongly here because of the crucial distinction between viewing climate change with still-hopeful urgency as opposed to fear-based alarmism or doomism. We will return to this theme shortly.

CarbonBrief’s synthesis also notes some further findings on 2023’s continued contribution to sea level rise and cryosphere melting. These derivative effects are mainly incremental compared to prior years and (except for record-setting drops in Antarctic sea ice extent) do not show the large changes observed for temperature.

Switching to the human realm, 2023 saw continued increases in greenhouse gas emissions for the three largest contributors to warming – carbon dioxide, methane and nitrous oxide. Worldwide, best estimates by the Global Carbon Project (the go-to source used by climate scientists for carbon cycle data) project a 1.1% increase in CO2 emissions for 2023, continuing the roughly 1% per year increase since 2010. This overall number masks wide variations around the world: India and China, the two most populous countries, increased emissions by about 8% and 4%, respectively, compared to 2022, while the European Union and US showed respective decreases of 7% and 3%. A separate analysis of US emissions by the Rhodium group yielded a smaller 2% drop in 2023, which came in part from continued decrease in coal use. Coal, by far the dirtiest fuel, now contributes just 17% of the energy to generate electricity in the US – less than either renewables or nuclear fission. Unfortunately, the contribution of natural gas to the US grid increased in 2023, as did emissions from transportation and industry. Most experts agree that emissions will soon begin to decline in those two sectors as the incentives of the 2022 Inflation Reduction Act kick in, but it is still too early to see these effects in the data.

It is worth taking a moment to recognize that the emissions data we rely on is far from perfect. For the most part, the numbers reported by national governments come from combining direct measurements with statistics on how much fossil fuel is extracted and used throughout the economy. This information then gets processed through climate and energy models to yield the reported estimates. Some of the raw numbers are reliable: for example, the amount of crude oil refined into gasoline and the consequent emissions can be precisely calculated. But CO2 and methane emissions in agriculture and some other sectors are much more difficult to measure, and some countries and private industries cannot be counted on to report reliably. This problem was recently highlighted by satellite detection of methane plumes using infrared imaging, showing leakage hotspots from fossil fuel infrastructure in the US Permian basin and elsewhere – hotspots wholly unaccounted for in EPA reports of US methane emissions.

Climate Trace, a coalition of academics and nonprofits founded by Al Gore and others a few years ago, is addressing this issue though what it calls “radical transparency.” The group assembles satellite measurements of emissions from around the world, with its latest assessment including a staggering 352 million greenhouse sources. It combines these data with ground measurements where available and reliable, and then trains an AI algorithm to use the satellite data to predict what is happening elsewhere on the ground. With this approach, presented last month at the COP28 meeting, Climate Trace estimates that in 2021 about 5% of global CO2 emissions went unreported. Satellite infrared measurements can be used to detect carbon dioxide, methane and nitrous oxide alike, making the approach of potentially broad utility. Gore hopes to embed this work into UN processes, seeing it as particularly useful for developing countries to more accurately determine their emissions.

So the year-end reports are telling us that temperatures are spiking and global emissions have yet to begin their decline, but renewable energy, at least, is offering a bright spot. The International Energy Agency just released its 2023 report on renewables, together with a forecast for the next five years that projects how close we may come to meeting the COP28 goal of tripling renewables capacity by 2030 – as needed to stay on track for net zero emissions by 2050. The IEA documents an astonishing 50% increase in renewables last year, driven especially by explosive growth in China. Gains in solar power are particularly strong given a 50% price drop for photovoltaic cells, and solar and onshore wind power are now both cheaper to build than fossil fuel plants. These factors drive IEA projections of 250% growth in renewables by 2030, within striking distance of the goal. Financing, though, still remains a challenge in many parts of the world. In particular, the IEA forecasts for growth in wind power, especially offshore wind, have been tempered in light of that reality. A number of recent high profile project cancellations and slowdowns in the buildout of new US East Coast offshore wind farms attest to this roadblock.

How should we look at all these data? I am struck by two lengthy recent interviews in the New York Times, both by the Talk columnist David Marchese, which highlight the sharp divergence in views among climate activists. One piece, an interview with Swedish professor and writer Andreas Malm, is a dark exploration of the psyche of a radicalized individual who, in his 2021 book “How to Blow Up a Pipeline,” advocated violence against fossil fuel infrastructure to combat what he sees as the ineffective, complacent tactics of the mainstream healthy climate advocacy movement. Malm justifies violence by arguing that what he advocates is nothing compared to the death and destruction wrought by fossil fuels, and clearly implies that any “accidents” that might accompany property destruction would be acceptable as collateral damage. Unsurprisingly, the Times interview was immediately picked up by the right-wing Fox News, which was more than happy to highlight Malm as a representative of climate activism. The Fox story conveniently also noted that the Times has published a guest piece by Malm in which he praised the group Just Stop Oil, which defaces art works to draw attention to the climate crisis. And so the culture wars escalate by another notch.

The roots of Malm’s point of view are easily discerned. Malm tells Marchese that “all attempts to rein in this [climate] problem have failed miserably,” that “there are no risk-free options left” and that he fundamentally disagrees with “the idea that there is progress happening.” To be fair, Malm is willing to go deep with his interviewer, even going so far as to reveal what he has learned from psychoanalysis, and acknowledging that his daily affective state is one of great despair. Malm is clearly intelligent, and doing perhaps the best job one can at presenting the idea of property violence as reasonable given our circumstances. He knows about the growth of renewable energy and carbon capture technologies, yet immediately discounts that they could be of value. Malm is rooted in his despair and, somehow, prevents himself from objectively looking at the good news together with the bad.

The corrective to the dark Malm piece is Marchese’s interview with the Scottish data scientist Hannah Ritchie, a researcher at Oxford University and editor of Our World in Data, a nonprofit dedicated to the use of research and data to solve our most pressing problems. If that organization has a patron saint, it must be the late professor and educator Hans Rosling, whose book Factfulness is a remarkable outpouring of viewpoint-altering critical thought, all grounded in basic facts about the world that somehow many people, even highly educated professionals, have failed to learn.

If years of insightful online writing were not already enough, in her new book Not the End of the World, Ritchie emerges as Rosling’s worthy successor. In eight chapters covering a broad range of environmental problems, including climate change, Ritchie delivers hardheaded analysis based on the conviction that, as she tells Marchese, it is possible to build an optimistic and influential narrative about global progress that is grounded in reliable data. The book details advances being made in areas like curtailing deforestation, enhancing food supply, and building out the infrastructure for renewable energy, in the process chipping away, bit by bit, at the doomist worldview that does a great deal of harm – in no small measure by undercutting the validity of science. Ritchie points out that in our current political environment, right-wing denialists are able to conflate what doomists say with actual science, thus undermining the scientific worldview when the latest prognostication again turns out to be false. The book, a mature outpouring of thought on our most pressing environmental problem, is indeed an antidote to that. The subtitle, “How We Can Be the First Generation to Build a Sustainable Planet,” says it all.


Thanks to a diligent Earthward reader for pointing out that reference lists are more useful when annotated!

COP28 agreement: 

China-US cooperation:

CarbonBrief’s 2023 state of the climate report:

Berkeley Earth global temperature report, 2023:

NOAA/NASA analysis:

WMO analysis, press release:

Dr. Jim Hansen’s analysis:

Jim Hansen – politics:

Global Carbon Project – 2023 emissions estimates:

Rhodium group analysis of 2023 US emissions:

Map of methane leaks in the US Permian basin:

Climate Trace greenhouse gas emissions tracking:

Climate Trace report at COP28:

IEA 2023 renewables report:

CarbonBrief’s synthesis of IEA renewables report:

Andreas Malm interview:

Fox News piece on the NY Times Malm interview:

Hannah Ritchie interview:


Not the End of the World:

Welcome to the Earthward Newsletter. Earthward is a weekly nonpartisan newsletter that covers recent events in the climate and renewable energy space, including science, technology, policy, politics and citizen advocacy.

Subscription is free and will generate one (1) weekly email that will arrive on Thursday mornings. The email will include an “unsubscribe” link. 

Earthward is written by Dr. John Perona and is an outgrowth of the climate education work begun with From Knowledge to Power: The Comprehensive Handbook for Climate Science and Advocacy (K2P).