Union of Concerned Scientists Global Warming

President-elect Donald Trump seems hell-bent on filling his cabinet with anti-science extremists, including climate science deniers. While these nominations are dangerous, what’s even more disturbing is the opening they create for fossil fuel corporations that have masterminded climate deception campaigns to regain social license. ExxonMobil, Shell, and trade associations like the American Petroleum Institute now profess to accept climate science—even as they exacerbate the crisis by continuing to expand fossil fuel production and kick the climate action can down the road with greenwashing and doublespeak.

In a cynical effort to please climate-conscious investors, ExxonMobil Chair and CEO Darren Woods may choose to keep climate science deniers like DOE nominee Chris Wright at arm’s length. But with global temperatures rising, the carbon budget dwindling, and climate-driven disasters affecting people and communities around the world, we cannot afford to accept ExxonMobil, Shell, or other major fossil fuel corporations as the lesser evil—or even worse, as integral to climate solutions.

Trump reignites overt climate denial

During his campaign, Trump sought $1 billion from oil and gas CEOs in exchange for a pledge to reverse environmental regulations and prevent new policies from being enacted. Since Trump’s election to a second term, fossil fuel industry interests have published their wish lists—and patrons have been rewarded with appointments to key posts in the administration. And we’ve already seen a resurgence of outright climate science denial.

Chris Wright, Trump’s nominee for Energy Secretary, has denied the well-established connection between climate change and extreme weather events. Liberty Energy, the fracking corporation he heads, describes its Environment, Social, and Governance (ESG) focus as delivering secure, reliable, affordable access to energy. Its ESG report downplays the urgency of the climate crisis and misrepresents the findings of the Intergovernmental Panel on Climate Change. This deliberate distortion of ESG builds on years of anti-ESG efforts by far-right activists including Vivek Ramaswamy, appointed by Trump to partner with fellow billionaire Elon Musk in weakening federal regulations and slashing government spending (notably, oil and gas subsidies are not on the chopping block).

Congressional allies pump up oil and gas

Meanwhile, on Capitol Hill, the Republican-led House Judiciary Committee has continued its attack on ESG investing, most recently in an unhinged report that rallies behind ExxonMobil against an alleged “cartel” of climate-conscious investors. The committee seems to be living in an alternate reality in which investors using market tools to influence corporate strategy is somehow illicit, while fossil fuel companies colluding to fix prices is not. The Judiciary Committee’s upside-down world is detached from reality, ignoring both record high US oil and gas production under the Biden administration and the fact that renewables continue to be cheaper than fossil energy.

Representative Jim Jordan’s Judiciary Committee embraces anti-climate positions that ExxonMobil itself long ago abandoned, alleging that commitments to reach net zero global warming emissions by 2050 are part of a “left-wing climate agenda.” Does ExxonMobil, the nation’s largest energy corporation, really need protection by a paternalistic Congress against powerful bullying investors? More likely, ExxonMobil recognizes that to compete in the global market, it must convince investors that it is taking action to reduce heat-trapping emissions and limit the worst effects of climate change. (As my colleague Dr. Carly Phillips has shown, ExxonMobil’s recent climate reports are misleading at best, dishonest at worst—textbook examples of greenwashing).

Major fossil fuel corporations lit the fuse decades ago

Climate change denial is no accident. It was plotted decades ago by the fossil fuel industry—for example, in an infamous 1998 memo by a task force of the American Petroleum Institute, which said that “Victory will be achieved when average citizens understand (recognize) ‘uncertainties’ in climate science.” As my UCS colleagues and I wrote in the Climate Deception Dossiers, this plan was eerily reminiscent of the tobacco industry’s strategy, succinctly described in an internal corporate memo as, “Doubt is our product…”

Source: UCS

The fossil fuel industry’s concerted disinformation campaign has been so successful that ExxonMobil, one of the ringleaders, can now claim to accept climate science while cronies like Chris Wright and Jim Jordan continue to stoke doubt.

Fossil fuel interests have been in Trump’s inner circle from the jump

In 2016, President Trump tapped ExxonMobil Chair and CEO Rex Tillerson as his Secretary of State. As I wrote at the time, Tillerson was an inappropriate and deeply troubling pick for the post, for countless reasons—here were five of the most distressing ones.

One of those reasons was the ways Tillerson doubted and downplayed climate change. And after his service in the Trump administration, the Wall Street Journal revealed new evidence that Tillerson had dismissed the Paris Agreement’s goal of keeping global temperature increase to well below 2 degrees Celsius above preindustrial levels (and striving to limit it to 1.5 degrees Celsius) as “something magical.” Worse still, just months before the agreement was signed, Tillerson asked, “Who is to say 2.5 is not good enough?”

Climate scientists, backed by robust research, say so. The IPCC Special Report on Global Warming of 1.5° C found that surpassing 2 degrees C of warming would significantly increase the frequency and severity of climate impacts, including extreme weather events, biodiversity loss, and threats to human health and livelihoods. However, limiting warming to 1.5 degrees C, could substantially reduce these risks, highlighting the critical importance of ambitious global climate action.

In 2017, Tillerson said he disagreed with President Trump’s decision to withdraw the US from the Paris Agreement. He was fired from his position in the administration just nine months later.

ExxonMobil hides behind extremists

ExxonMobil is staking out a different position in the second Trump administration.

2024 wrapped up as the hottest year on record, with warming temporarily reaching 1.5 C. Unlike Tillerson or Trump, current ExxonMobil Chair and CEO Darren Woods professes to support the Paris Agreement. However, the corporation pushes technological “solutions” that can’t bend the emissions curve steeply downward in the critical period between now and 2030.

In December, ExxonMobil released its plan to 2030, which calls for an 18% increase in oil and gas production, thanks largely to growth in the Permian Basin (after last year’s acquisition of Pioneer) and offshore Guyana. Woods bragged about reducing ExxonMobil’s upstream (exploration and production) emissions intensity by 20% between 2016 and 2023—and says it is aiming to cut emissions intensity 40-50% by 2050.

However, upstream emissions intensity measures emissions per unit of production—and excludes emissions from burning oil and gas, which constitute roughly 85 percent of the heat-trapping emissions attributable to ExxonMobil. So, if production is increasing—as ExxonMobil’s is—absolute emissions will continue to climb even if upstream emissions intensity significantly decreases.

The corporation says it is pursuing “up to $30 billion in lower-emissions investment opportunities”—which for ExxonMobil means carbon capture and storage (CCS), hydrogen, and lithium. Among other projects, ExxonMobil’s Low Carbon Solutions business is developing a Texas plant to produce hydrogen from fossil gas (if the tax credit included in the Inflation Reduction Act survives) and a gas-fired power plant to support a data center. (Read more about how data centers’ rapidly growing energy use is changing electricity supply and demand—and what it means for energy infrastructure planning—in this blog by my UCS colleague Mike Jacobs).

Fossil fuel lobbyists grab seats at the table

ExxonMobil’s Woods was one of more than 1,770 fossil fuel industry lobbyists granted access to the annual UN climate negotiations (COP29) in Baku, Azerbaijan. The heads of Aramco, BP, and TotalEnergies were also registered to participate as guests of the host country.

Woods made headlines when he discouraged US President-elect Trump from withdrawing the United States from the Paris Agreement. Although some media outlets credited Woods with supporting climate policy and pushing back against Trump’s anti-climate agenda, what he actually said was, “The way you influence things is to participate, not to exit.” What I see in the oil and gas industry’s participation at COPs is not a commitment to climate action, but the determination—and access—to interfere with a fair, fast, and funded phaseout of fossil fuels by the international community.

What to watch out for in 2025

As 2025 begins, the challenges for climate advocates are at least threefold: 1) mobilizing fierce opposition and marginalizing climate science deniers who secure positions of power in Congress or the administration; 2) inoculating state, federal, and international policymakers against deception and greenwashing by ExxonMobil and other major fossil fuel corporations; and 3) defending and expanding the use of ESG investment strategies against bad-faith Congressional “oversight.”

With federal climate and clean energy policies likely to be stalled or rolled back, climate litigation is a key arena for progress in the United States. Preserving access to justice through the courts will be essential, in the face of veiled threats against climate-related litigation in Project 2025 and Trump’s promise to stop climate accountability litigation against the oil and gas industry.

The fossil fuel industry will attempt to cash in on its political influence in the United States by advancing deregulation, facilitating increased oil and gas production on federal lands and waters, expanding subsidies and other giveaways, blocking mandatory climate disclosure, evading liability for climate damages and corporate misconduct, and stoking political and legal attacks against activists and organizers. As President-elect Trump opens the floodgates to all kinds of disinformation—including climate science denial—some pro-fossil forces will fight climate and clean energy policies directly. But others will more stealthily seek to delay and undermine the transition away from fossil fuels, claiming to support climate action while defining “climate solutions” in their narrow short-term interests. These efforts to regain social license by those most responsible for the climate crisis are particularly insidious.

Both approaches—and the actors who employ them—endanger our health, environment, energy security, human rights, and democracy. Even as we steel ourselves to refute a barrage of lies from top officials in the Trump administration and Congress, we must resist compromising with leaders of an industry that has deceived the public and policymakers for decades, evaded accountability for the harm it has caused, continues to obstruct the urgent transition to renewable energy, and has not earned the public’s trust.

The year 2023 was by far the warmest in Earth’s recorded history, and perhaps in the past 100,000 years, shattering the previous record set in 2016 by 0.27°C (0.49°F). According to recent data from NOAA’s National Center for Environmental Information, 2024 is likely to be even warmer than 2023.  

Scientists are sounding the alarm because this warming is shockingly big—bigger than what we would have expected given the long-term warming trend from fossil fuel-caused climate change. But why were 2023 and 2024 so warm? 

The reason why 2016 was so warm was because of a strong El Niño event—a naturally-occurring cycle in the Earth’s climate system—which typically leads to a spike in Earth’s global-mean temperature. In that year, El Niño added to the increased warming caused by the build-up of heat-trapping emissions in the atmosphere, leading to that record-breaking heat. 

This is why 2023 and 2024 are so alarming: El Niño was only moderately strong (contributing a small amount of warming) in 2023 and was in a neutral state for most of 2024 (contributing almost no warming), so we cannot attribute the record-breaking warmth of  2023 and 2024 to El Niño like we did in 2016, and we definitely should not be shattering heat records under a neutral state El Niño. In other words, 2023 and 2024 have been much hotter than scientists’ predictions. 

What could be a potential explanation for the record-breaking warmth? This question was a focus at the 2024 annual American Geophysical Union (AGU) meeting in Washington, D.C., where 30,000-plus scientists gathered to present their latest research. The two leading theories to explain the record-breaking warmth are a reduction in tiny particles in the atmosphere called aerosols due to shipping fuel regulations that reduced sulfur oxide (SOx) emissions, or decreasing cloud cover. Before we get to those two likely culprits, let’s talk about albedo. 

What is albedo?

A concept that’s important in both of these theories is planetary albedo. Albedo is the total reflection of incoming solar radiation by Earth. This reflection is done partially by lighter-colored surfaces such as ice sheets and ice shelves, clouds, deserts, and also by aerosols. Think of walking outside on a sunny day after a snowstorm or in a desert; the sun’s rays are reflected by the light surface, making it harder to see. These solar rays are normally reflected out to space. 

The planet typically reflects about 30% of incoming solar radiation, but this number can change slightly depending on how much snow- or ice-cover there is, on the amount of cloud cover, or on how many aerosols are in the atmosphere (remember, these are tiny atmospheric particles that reflect light). Humans have a direct effect on albedo through emitting industrial aerosols such as sulfates, which accumulate in the atmosphere due to the burning of fossil fuels. 

You might be thinking, “if the burning of fossil fuels increases Earth’s albedo due to additional aerosols in the atmosphere, shouldn’t this offset any impact from the effects of increased heat-trapping emissions like carbon dioxide?” It’s a great question, but the warming effect from heat-trapping gases far outweighs the cooling effect from industrial aerosols. 

Reduction in aerosols leads to albedo decrease 

A popular theory that could explain why the past two years have been so warm has to do with a change in aerosol emissions due to new shipping fuel regulations aimed at helping to address pollution that harms health and the environment. In 2020, the International Maritime Organization (IMO) reduced the limit on the amount of sulfur in ships’ fuel oil, which then led to a reduction in sulphur dioxide and particulate matter emissions which form aerosols in the atmosphere.  

According to two recent studies, this reduction in aerosols may have led to a spike in the global-mean temperature. How? As industrial aerosols decreased due to this new regulation, particularly over the North Atlantic Ocean, the planetary albedo slightly decreased, which means that more incoming solar radiation was absorbed by the planet rather than reflected. 

However, another study found that the effect of additional industrial aerosols in the atmosphere would only affect global-mean temperature by a couple hundredths of a degree, rather than the 0.27°C observed in 2023. 

Of course, continuing to strengthen public health-based standards to cut harmful air pollution from burning fossil fuels, including sulphur dioxide and particulate matter, is essential and lifesaving. Further scientific work is underway to help advance our understanding of how and how much this contributes to changes in industrial aerosols and how that may be influencing the rate of warming. Meanwhile, sharply cutting our use of fossil fuels is the best way to limit carbon dioxide (CO2) emissions, the primary driver of climate change.  

Diminishing cloud cover due to warming creates more warming 

A study released just last month, and another preprint of a study presented at AGU, provide a different explanation for the spike in global-mean temperature: clouds. In this case, the authors of both papers argue that a decrease in cloud cover led to the decrease in planetary albedo.  

Over the last few decades, there has been an observed decrease in total planetary cloud cover, especially over the North Atlantic Ocean off the Northeast US coast. Here, low-level cloud cover has decreased drastically, mostly related to an increase in ocean surface temperature.  

The decrease in low-level cloud cover due to warming ocean surfaces is particularly alarming because the process could be the manifestation of a feedback associated with global warming: as the oceans warm, low-level cloud cover decreases, which results in a lower planetary albedo and thus a faster warming world. 

Ocean surface temperatures in the North Atlantic could also be warming so much due to a weakening of the Atlantic Meridional Overturning Circulation (AMOC), which I blogged about in November. While ocean surface temperatures are increasing globally due to fossil fuel-caused climate change, they are warming even faster off the US Northeast coast, which could be the result of the AMOC slowing down and pooling warm water in the region. 

Important questions are still being sorted out 

Climate scientists are still trying to figure out what exactly made 2023 and 2024 so warm. We discussed some potential reasons that could explain the spike in warming, but the details haven’t been ironed out quite yet. 

What’s interesting is that the sudden warming could also be due to a combination of the two theories.

Did you know that in order for water droplets to form in the atmosphere to create clouds, they need a tiny particle to condense onto? These tiny particles are called cloud condensation nuclei (CCN), and one type of CCN is industrial aerosols such as sulfates. After the IMO lowered sulfur in shipping fuel oil, less sulfate aerosols in the atmosphere could have resulted in less CCN available for cloud droplets to form, resulting in a lower planetary albedo. 

To perhaps add another layer to everything, during my PhD research, I studied how different patterns of ocean surface temperature affect the rate of global warming. For example, if the West Pacific warms more than the rest of the world, then the planet will actually warm at a slower rate than if that warming was distributed evenly across the ocean’s surface. 

We found that the most likely ocean surface pattern of warming in the near future, which is currently developing, will result in a rapidly warming planet. This could very well be a piece of the puzzle as to why 2023 and 2024 were so warm. 

Scientists continue to sound the alarm 

The additional warming in 2023 and 2024 adds a layer of complexity to fossil fuel-caused climate change (and not the kind of complexity we want, given that the planet seems to be warming more rapidly than before). These two ideas from the science community are still being ironed out, and it will take some more time to understand exactly what caused this spike in global-mean temperature. 

One thing is for sure though: the planet is warming mainly due to increased heat-trapping emissions in Earth’s atmosphere from the burning of fossil fuels. The only way to slow down warming is by reducing said emissions through a fast and fair transition to clean, renewable energy. 

Senators have the herculean task of ensuring that our nation’s future is in the hands of appropriate leaders. Through the Senate confirmation process, they are responsible for vetting nominees for the most senior leadership positions in federal agencies.

There are more than 1,300 positions requiring Senate confirmation, many of whom will shape policies and programs that rely heavily on scientific expertise and knowledge. These are positions critical to protecting public health and the environment, keeping the nation’s food and drug supplies safe, and advancing US interests. Senators need to ensure that nominees are the right fit for the job and avoid costly mistakes that risk human lives and the health of our planet.

Some positions you may have heard of include the Under Secretary for Nuclear Security for the Department of Energy; the Under Secretary of Defense for Research and Engineering for the Department of Defense; Administrators for the Environmental Protection Agency (EPA), the Department of Transportation, the National Aeronautics and Space Administration, and the National Oceanic and Atmospheric Administration (NOAA); and Directors for the National Institutes of Health and the National Science Foundation.

My colleagues have raised concerns already about President-elect Trump’s picks to lead the EPA, the Department of Housing and Urban Development, and the Department of Justice, and why the new NOAA administrator must understand and advocate for science.

Appointees’ Science Savvy Matters

Why should we care that presidential appointees know how to understand and apply science appropriately in their decision making? One key reason is that President-elect Trump’s scientific understanding does not inspire confidence, so senators should at least make sure the people running the executive branch have a firm grounding in science.

Perhaps you remember “Sharpiegate” in 2019, when then-President Trump doctored the forecast path of Hurricane Dorian with a black Sharpie maker. He altered the official weather forecast to suggest the hurricane might strike Alabama. Despite corrections from the National Weather Service, President Trump continued to insist he was correct, creating public confusion about who needed to evacuate and where emergency response resources would be needed. This put American lives and livelihoods at risk and wasted taxpayer dollars.

Senators evaluating nominees who will oversee policies and programs deeply rooted in science should vet them for the following:

1. Strong scientific background. Does the nominee know their quarks from their quasars or their atoms from their amino acids? Do they consult bona fide experts in the subject matter?  Do they check for people posing as experts who are really purveyors of disinformation or misinformation?  Do they check the potential conflicts of interests of the experts they consult? A strong grasp of technical material is essential for making rules that keep us safe, for instance from environmental contaminants such as the carcinogenic gas ethylene oxide.
2. Analytic skills. The nominee should be able to analyze complex data, interpret scientific research, and apply findings to policy or program development and implementation. Maximizing electric grid reliability, for instance, requires our leaders to integrate data about the costs and benefits of energy storage options considering multiple factors such as local growth projections, increased electricity demand, solar and wind profiles over time, energy generation by fossil gas technologies, and policy incentive impacts.
3. Critical thinking. Look for someone who questions assumptions, even questions their questions about the assumptions! A nominee should be aware of the heuristics and biases that challenge all human cognition and set up strategies to address these limitations. For instance, biases that block funding for all federal research that uses fetal tissue put at risk advancements in vaccines, transplants, and treatment of degenerative diseases like Parkinson’s.
4. Communication skills. The nominee must be able to communicate complex scientific concepts so clearly that your grandma (and even the President) will understand. For instance, explaining nuclear toxicology concepts is important for helping the public understand why and how to avoid radiation exposure.
5. Problem-solving abilities: They should be adept at identifying problems and developing innovative, science-based solutions. There will be no shortage of opportunities to test this skill, especially during periods such as “danger season,” the time of year when climate change impacts like hurricanes, extreme heat, and wildfires peak and collide with one another.
6. Ethical judgment: Senators must ensure the nominee has a strong sense of scientific integrity and intellectual honesty, as they will be making decisions that can significantly impact public health and safety. Why? Because lives and livelihoods are at risk. Lessons from prior administrations and examples of anti-science actions during the first Trump administration are well-documented by UCS.
7. Collaboration and teamwork: The nominee should play well with others, including scientists, policymakers, and members of the public who are directly or indirectly affected by their programs. The nominee has a particular responsibility to respect and defend the federal scientific workforce because these experts are essential for keeping people and our planet safe and healthy.
8. Adaptability: Having the ability to adapt to new scientific developments and changing policy landscapes is a must because science evolves, as does the social-ecological system scientists are working within. Nominees will need to integrate the latest science with other considerations as they decide on the optimal solutions to complex problems.
9. Leadership skills: This includes the ability to inspire and guide teams, and to make tough decisions when necessary. The captain of the ship needs to navigate through a sea of scientific jargon, uncertain evidence, and different assumptions and values. Dialogue on the New Strategic Arms Reduction Treaty is just one example issue where leadership plays a critical role in global stability, in this case in preventing a runaway arms race.
10. Passion for public service: A genuine commitment to using science to benefit society and improve public policies is a must. Taxpayer dollars will pay this nominee’s salary, so I want them acting in my best interest.

Some of these might seem like “no duh” suggestions. But we don’t have to look too far back to see when a lack of scientific expertise, a lack of respect for scientific methods, or a predilection for ignoring science resulted in preventable death and disease, or profound harm to our planet. For senators who find science daunting, this simple rubric can help to highlight who should be trusted to lead federal departments and agencies that rely on science to address the important concerns and needs of their constituents.

As 2024 winds down, with its parade of climate-and extreme weather-fueled disasters, people across the nation are feeling the sharp pinch of rising insurance premiums and dropped policies. There are other factors at play here—including growing development in flood-prone and wildfire-prone areas and fundamental inequities and information gaps in the insurance market—but all of that is being exacerbated by worsening flooding, wildfires and intensified storms. Policymakers and regulators must act quickly because the market is not going to solve this problem on its own, and it’s definitely not going to do it in a way that protects low- and middle-income people. 

Please see earlier blogposts I’ve written on this topic to learn more.  

More data transparency is urgently needed 

Despite the many headlines and heart-breaking stories about the impact of high insurance costs and dropped policies, there’s a lack of publicly available, granular data on where and how much premiums are increasing and why.  

Earlier this year, the US Department of the Treasury’s Federal Insurance Office (FIO) and the National Association of Insurance Commissioners (NAIC) announced a first-ever data call to assess how climate risks were affecting the insurance market. This is a voluntary effort and some states, including Florida, Texas and Louisiana, have already signaled they will not participate. That’s a problem because these are also states where consumers have experienced sky-rocketing rate increases and insurers dropping policies or even exiting the market entirely—and they are highly exposed to climate risks. 

According to an annual report from the Financial Stability Oversight Council (FSOC), “The data call required participating insurers to submit ZIP Code-level data on premiums, policies, claims, losses, limits, deductibles, non-renewals, and coverage types for the ZIP Codes in which they operate nationwide. State insurance regulators sought more than 70 data points. An anonymized subset of the data was shared with FIO.”  

Yet, none of that data has been shared publicly. That’s why UCS has joined in signing a letter from a group of organizations, calling on FIO to release the data so it’s available for local planners, policymakers, decisionmakers, scientists and community-based organizations to have a better understanding of how best to address this rapidly growing problem.  

Private insurers are holding a lot of proprietary data that regulators and the general public do not have access to. This creates a gap in information—an information asymmetry—that can prevent people from making informed decisions and prevent the market from functioning well. A lack of freely available, localized information about climate risks and projections is also part of the challenge for many communities and homeowners.  

Congressional oversight is needed 

The insurance crisis is now a nationwide problem, spilling into parts of the country that may not yet be on the frontlines of climate risks, and into the broader insurance market beyond property insurance. Congress must step up to examine the problem and propose solutions, working alongside state regulators.  

That’s why it’s heartening to see that Senator Sheldon Whitehouse (D-RI) and the Senate budget committee are holding a hearing on December 18 on the climate-driven insurance crisis. Among the witnesses is Dr. Benjamin Keys, who has done important work in highlighting the role of climate risks in driving increases in insurance premiums.  

According to his research, homeowners in the US saw their annual insurance premiums increase by an average of 33% or $500 between 2020 and 2023. Further, his work analyzing premium increases at the county level shows a stark correlation with places that are more exposed to climate risks.  

Average annual insurance premiums in the first half of 2023 by county 

Source: Keys and Mulder, 2024 https://www.nber.org/system/files/working_papers/w32579/w32579.pdf 

Earlier this week, Democrats on the Joint Economic Committee, chaired by Senator Martin Heinrich (D-NM), released a report highlighting the growing risks of climate change to insurance and housing markets.  

The non-partisan Congressional Budget Office has also released a recent report and conducted recent briefings on climate change, disaster risk and homeowner’s insurance. One of the challenges they point out is that, even as disasters are worsening, many people are underinsured.  

Low- and moderate-income households are more likely to be underinsured. According to their report: “In 2023, insurers covered $80 billion of the $114 billion of losses attributable to natural disasters, meaning that 30 percent of those losses were not insured.” With insurance premiums increasingly unaffordable, that gap in insurance will likely increase as many people may be forced to go without.  

There are important ways insurance affordability could be tackled by policymakers, including increasing access to parametric insurance, microinsurance programs, and community-based insurance, as well as passing legislation to include means-tested subsidies in the National Flood Insurance Program. Parametric insurance contracts can help simplify and speed up payouts since they are set up based on specific disaster thresholds being crossed (e.g. an earthquake of a certain magnitude or a hurricane with a specific wind speed), rather than being based on an actual evaluation of loss which can take time. Microinsurance programs can provide low-income households access to basic insurance with lower premiums and less comprehensive coverage. Community based insurance is purchased at the community level instead of individual households.  

Insurance companies should also be required to provide more information about why they are increasing rates, how they determine the magnitude of the increases, and what incentives they provide to help homeowners reduce their premiums by investing in risk reduction measures. Regulators must ensure that insurers are not discriminating against low-income policyholders or dropping less profitable lines under the guise of climate impacts.  

Time to act

The crisis in the insurance market we’re seeing today was entirely foreseeable, and largely preventable if we had acted earlier to limit the heat-trapping emissions driving climate change, invest in climate resilience, and enact equity-focused reforms in insurance markets. Climate scientists have been sounding the alarm for decades, and yet the market and policymakers have reacted with short-term strategies because those are the timeframes for determining shareholder value, profits and elections.  

As we look to find ways out of this crisis, let’s keep in mind the continued mismatch in time horizons for decision making in the insurance marketplace and the climate impacts we have unleashed and are locking in for the long term by continuing to burn fossil fuels today. And, in an outrageous contradiction, the insurance industry continues to insure the build-out of fossil fuel infrastructure! 

Data from Swiss Re shows that, globally, insured losses will exceed $135 billion in 2024. Two thirds of that happened in the US, with Hurricanes Helene and Milton alone causing $50 billion in insured losses.

US insurance companies will very likely hike rates again in the new year as global reinsurers reset their rates to reflect the growing costs of disasters worldwide. Rate hikes will hit homeowners hard. Renters, too, as landlords are increasingly passing through this increase in insurance costs in the form of higher rents, thus worsening the housing affordability crunch. More people will find their monthly budgets stretched or be forced to go without insurance and live in fear that they won’t be able to recover from the next disaster.  

The question for policymakers and regulators is whether they are willing to take bold action to help keep insurance available and affordable wherever possible (which unfortunately won’t be everywhere); help people invest in resilience measures to keep their homes and property safer in a warming world; help provide options for people to move away from the highest risk places; and help cut the heat-trapping emissions driving many types of extreme disasters.  

Insurance is one important tool. Let’s make sure it’s working well, guided by the latest science and with strong oversight and equity provisions. And let’s invest in a whole range of necessary actions to complement that because the current insurance crisis is likely just the tip of the iceberg.  

Climate risks are not just affecting the insurance market but also the housing and mortgage markets. And it isn’t just insurance that is increasingly hard to buy, finding safe, affordable housing in places protected from climate extremes is a growing challenge for many low- and middle-income people. 

One thing we can’t afford our policymakers and decisionmakers to do is to deny that climate change is an economic and pocketbook issue.  

As the days grow shorter and I prepare for the holiday season, it’s a fitting moment to reflect on the state of climate litigation—a field that continues to evolve as both a tool for accountability and an arena for climate action. In the past year, we’ve seen significant victories that inspire hope, like the Swiss KlimaSeniorinnen case, which called for an improved government climate action plan; Held v. Montana, where young plaintiffs won the first U.S. trial court ruling affirming a constitutional right to a safe climate; and in Hawaii, which settled a landmark transportation-related case that will fund critical efforts to decarbonize its transit system. These victories illustrate the power of courts to advance meaningful progress in climate governance and highlight the growing importance of science and scientists in providing the evidence needed to inform these legal decisions. 

Yet, progress often feels frustratingly slow. In the U.S., cases challenging fossil fuel companies for decades of climate disinformation remain stalled, tied up by the defendants in procedural wrangling that prevents them from being heard on their merits, delaying justice for affected communities. It’s a familiar frustration: will 2025 finally be the year these cases move forward?  

While I’ve learned not to make bold predictions on this front, I remain cautiously optimistic. In fact, last week the U.S. Department of Justice weighed in on this with two key Supreme Court briefs supporting state-level climate lawsuits. In both cases, the DOJ sided with local governments, arguing that their claims against fossil fuel companies for misleading the public about climate harms should proceed under state law. These briefs underscore a clear federal stance on the importance of preserving state-level legal avenues to address deceptive practices.  

Although US Courts in the U.S. have made progress in hearing other types of climate-related cases, the lack of substantive rulings in disinformation lawsuits is a glaring gap. 

Similarly, even cases that appear to be securing meaningful outcomes often face uncertainties. In the Milieudefensie et al. v. Shell case, for instance, the Dutch courts upheld the ruling that Shell must act to reduce emissions in line with the Paris Agreement. However, the appeal process revealed uncertainties about the precise scale and timing of these reductions, exposing challenges of translating scientific evidence into clear legal mandates. 

This tension—between exciting breakthroughs and persistent delays—underscores the complexity of litigation’s role in climate governance. Courts are emerging as critical players in climate action, especially as a lack of political will and obstruction by fossil fuel interests continue to impede bold outcomes and accountability in international processes like the COP negotiations. I previously wrote about expectations for the incoming Trump presidency, positioning courts as an essential backstop for accountability in the U.S. in the absence of federal leadership. 

The ability of courts to enforce obligations, act on science, and elevate human testimony has never been more crucial. With this in mind, here are three key developments that I believe will shape climate litigation in 2025. 

International Courts Grapple with Climate Change Action  

2025 will undoubtedly be defined by the International Court of Justice (ICJ) and its advisory opinion on states’ obligations to combat climate change. The ICJ hearings, which wrapped last Friday, drew unprecedented global engagement, with a historic number of countries and organizations submitting arguments. These comments repeated an often-shared plea for justice, sustainability, and progress, emphasizing the need for international cooperation rooted in sound science and human rights. 

The ICJ’s advisory opinion has the potential to set a new benchmark for climate accountability. While not legally binding, such opinions hold significant moral and legal influence. They can guide future litigation, encourage governments to align their policies with scientific imperatives, and clarify the responsibilities of states under international law to protect vulnerable populations from climate harms. 

This moment at the ICJ builds on a growing trend of international courts stepping into the climate governance arena. In 2024, the International Tribunal for the Law of the Sea (ITLOS) issued a landmark advisory opinion affirming that greenhouse gas emissions constitute marine pollution under the United Nations Convention on the Law of the Sea (UNCLOS). ITLOS went further, clarifying the obligations of states to prevent, reduce, and control emissions, protect marine ecosystems, and collaborate internationally to address climate-related ocean impacts. While the ruling didn’t impose specific measures, it established UNCLOS as a legal framework for climate accountability that complements other treaties like the Paris Agreement and provides a pathway for legal action. 

Similarly, the Inter-American Court of Human Rights (IACHR) held hearings on climate change and human rights earlier this year, with a focus on the Americas. Submissions from states, NGOs, and individuals emphasized the disproportionate impact of climate change on vulnerable populations,  the need for regional cooperation, and corporate accountability. The IACHR’s forthcoming ruling could further solidify the link between climate action and human rights, providing another layer of legal precedent for addressing the climate crisis. 

Together, these international judicial interventions highlight a growing recognition of the courts as key arbiters in the fight against climate change. When diplomatic negotiations falter, judicial action serves as a complementary pathway, providing a critical counterbalance, grounded in evidence and accountability.  

A Surge in Greenwashing Litigation 

Another defining feature of 2025 will be the continued rise of greenwashing lawsuits. These cases, which challenge companies for making deceptive claims about their climate commitments or sustainability efforts, are becoming a cornerstone of climate litigation. Over 140 such cases have been filed globally since 2016, with 47 new filings in 2023 alone.  

Climate-washing lawsuits are particularly potent because they expose and disrupt the narratives corporations use to greenwash and bolster their reputations while continuing to contribute to the climate crisis. Recent cases have targeted sectors ranging from finance to consumer goods, and the scope is expanding. Courts have ruled against companies for overstating their “net zero” pledges, misleading consumers about the environmental impact of products, and greenwashing their financial products. 

As governments introduce stricter regulations on corporate sustainability claims and public awareness of greenwashing grows, this area of litigation is poised for significant expansion. Beyond penalizing false claims, these lawsuits send a clear message: corporations must back their promises with real, measurable action. 

Post-Disaster and Failure-to-Adapt Cases Gain Ground 

The growing prevalence of climate-related disasters—wildfires, hurricanes, floods—continues to drive litigation targeting both public and private entities. In 2024, lawsuits were increasingly filed in response to catastrophic events, including the Maui wildfires, which devastated communities and underscored systemic vulnerabilities.  

Similarly, earlier this month, the town of Carrboro, North Carolina, file a complaint against Duke Energy, alleging that the utility’s failure to transition from fossil fuels to renewable energy has contributed to intensified weather events, such as flooding and storms, causing significant harm to local infrastructure and residents.  These cases focus on holding governments and corporations accountable for failing to adapt to foreseeable climate risks or mitigate their impacts. 

As courts wrestle with these issues, they are shaping a new era of accountability. Post-disaster cases bring the abstract reality of climate change into sharp relief, translating emissions data into the lived experiences of communities harmed. In 2025, we can expect to see more cases that address the human cost of climate inaction while pushing for systemic change. 

The Critical Role of Courts 

Courts have the ability to enforce accountability in ways that are direct, timely, and rooted in evidence. However, the power of courts to affect change depends on the conditions we create for them to act. This includes fostering robust scientific research, empowering communities to bring cases, and ensuring that legal systems are equipped to handle the complexities of climate litigation. Efforts to integrate science more effectively into legal arguments, help judges accurately interpret technical evidence, and improve access to justice for climate-vulnerable populations are all critical to building a resilient legal framework. Reach out to get involved in our expert working groups and engage in this work with us. 

The ICJ’s deliberations, the rise of climate-washing cases, and the focus on disaster liability all point to the transformative potential of litigation to address the climate crisis. But these legal battles are just one piece of the puzzle. They must be complemented by bold policy action, international cooperation, and a collective commitment to protecting future generations. 

2025 holds immense promise, but it also demands care, creativity, and persistence. While we are facing great challenges in the U.S. and around the world, courts have shown they can play a transformative role in shaping our collective response to climate change. As we look to the year ahead, let us renew our resolve to leverage every available tool—legal, scientific, and political—to combat the greatest challenge of our time. Together, we can create the conditions for a more just, sustainable future.