Human-driven climate change is increasingly shaping the Earth’s living environments. Rising temperatures, rapid shifts in rainfall and seasonality, and ocean acidification are presenting altered environments to many animal species. How do animals adjust to these new, often extreme, conditions?

Animal nervous systems play a central role in both enabling and limiting how they respond to changing climates. As a biologist and neuroscientist, two of my main research interests involve understanding how animals accommodate temperature extremes and identifying the forces that shape the structure and function of animal nervous systems, especially brains. The intersection of these interests led me to explore the effects of climate on nervous systems and how animals will likely respond to rapidly shifting environments.

All major functions of the nervous system – sense detection, mental processing and behavior direction – are critical. They allow animals to navigate their environments in ways that enable their survival and reproduction. Climate change will likely affect these functions, often for the worse.

Shifting sensory environments

Changing temperatures shift the energy balance of ecosystems – from plants that produce energy from sunlight to the animals that consume plants and other animals – subsequently altering the sensory worlds that animals experience. It is likely that climate change will challenge all of their senses, from sight and taste to smell and touch.

Animals like mammals perceive temperature in part with special receptor proteins in their nervous systems that respond to heat and cold, discriminating between moderate and extreme temperatures. These receptor proteins help animals seek appropriate habitats and may play a critical role in how animals respond to changing temperatures.

Climate change disrupts the environmental cues animals rely on to solve problems like selecting a habitat, finding food and choosing mates. Some animals, such as mosquitoes that transmit parasites and pathogens, rely on temperature gradients to orient themselves to their environment. Temperature shifts are altering where and when mosquitoes search for hosts, leading to changes in disease transmission.

How climate change affects the chemical signals animals use to communicate with each other or harm competitors can be especially complex because chemical compounds are highly sensitive to temperature.

Formerly reliable sources of information like seasonal changes in daylight can lose its utility as they become uncoupled. This could cause a breakdown in the link between day length and plant flowering and fruiting, and interruptions to animal behavior like hibernation and migration when day length no longer predicts resource availability.

Changing brains and cognition

Rising temperatures may disrupt how animal brains develop and function, with potentially negative effects on their ability to effectively adapt to their new environments.

Researchers have documented how temperature extremes can alter individual neurons at the genetic and structural levels, as well as how the brain is organized as a whole.

In marine environments, researchers have found that climate-induced changes of water chemistry like ocean acidification can affect animals’ general cognitive performance and sensory abilities, such as odor tracking in reef fish and sharks.

Behavior disruptions

Animals may respond to climate adversity by shifting locations, from changing the microhabitats they use to altering their geographic ranges.

Activity can also shift to different periods of the day or to new seasons. These behavioral responses can have major implications for the environmental stimuli animals will be exposed to.

For example, fish in warming seas have shifted to cooler, deeper waters that have dramatically different light intensity and color range than their visual systems are used to. Furthermore, because not all species will shift their behaviors in the same way, species that do move to a new habitat, time of day or season will confront new ones, including food plants and prey animals, competitors and predators, and pathogens.

Behavioral shifts driven by climate change will restructure ecosystems worldwide, with complex and unpredictable outcomes.

Plasticity and evolution

Animal brains are remarkably flexible, developed to match individual environmental experience. They’re even substantially capable of changing in adulthood.

But studies comparing species have seen strong environmental effects on brain evolution. Animal nervous systems evolve to match the sensory environments of each species’ activity space. These patterns suggest that new climate regimes will eventually shape nervous systems by forcing them to evolve.

When genetics have strong effects on brain development, nervous systems that are finely adapted to the local environment may lose their adaptive edge with climate change. This may pave the way for new adaptive solutions. As the range and significance of sensory stimuli and seasonal cues shift, natural selection will favor those with new sensory or cognitive abilities.

Some parts of the nervous system are constrained by genetic adaptations while others are more plastic and responsive to environmental conditions. A greater understanding of how animal nervous systems adapt to rapidly changing environments will help predict how all species will be affected by climate change.

Sean O'Donnell does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

When this year’s United Nations Climate Change Conference begins in late November 2023, it will be a moment for course correction. Seven years ago, nearly every country worldwide signed onto the Paris climate agreement. They agreed to goals of limiting global warming – including key targets to be met by 2030, seven years from now.

A primary aim of this year’s conference, known as COP28, is to evaluate countries’ progress halfway to the 2030 deadlines.

Reports show that the world isn’t on track. At the same time, energy security concerns and disputes over how to compensate countries for loss and damage from climate change are making agreements on cutting emissions tougher to reach.

But as energy and environmental policy researchers, we also see signs of progress.

Global stocktake raises alarms

A cornerstone of COP28 is the conclusion of the global stocktake, a review underway of the world’s efforts to address climate change. It is designed to pinpoint deficiencies and help countries recalibrate their climate strategies.

A report on the stocktake so far stressed that while the Paris Agreement has spurred action on climate change around the globe, current policies and promises to cut greenhouse gas emissions still leave the world on a trajectory that falls far short of the agreement’s aim to limit warming to less than 1.5 degrees Celsius (2.7 Fahrenheit) compared with preindustrial temperatures.

Governments worldwide plan to produce twice as much fossil fuel in 2030 than would be allowed under a 1.5 C warming pathway, another U.N.-led report released in early November found.

Limiting global warming to 1.5 C rather than 2 C (3.6 F), may appear to be a minor improvement, but the accumulated global benefits of doing so could exceed US$20 trillion.

Escalating greenhouse gas emissions are the primary factor driving the rise in global temperatures. And fossil fuels account for over three-quarters of those emissions.

To avoid overshooting 1.5 C of warming, global greenhouse gas emissions will have to fall by about 45% by 2030, compared with 2010 levels, and reach net zero around 2050, according to the Intergovernmental Panel on Climate Change.

But emissions aren’t falling. They rose in 2022, surpassing pre-pandemic levels. The global average temperature briefly breached the 1.5 C warming limit in March and June 2023.

The global stocktake unambiguously states that, to meet the Paris targets, countries must collectively be more ambitious in cutting greenhouse gas emissions. That includes rapidly reducing carbon emissions from all economic sectors. It means accelerating adoption of renewable energy such as solar and wind power, implementing more stringent measures to stop and reverse deforestation, and deploying clean technologies such as heat pumps and electric vehicles on a wide scale.

The significance of phasing out fossil fuels

The report underscores one point repeatedly: the pressing need to “phase out all unabated fossil fuels.”

Fossil fuels currently make up 80% of the world’s total energy consumption. Their use in 2022 resulted in an all-time high of 36.8 gigatons of CO2 from both energy combustion and industrial activities.

Despite the risks of climate change, countries still provide huge subsidies to the oil, coal and gas industries. In all, they provided about US$1.3 trillion in explicit subsidies for fossil fuels in 2022, according to the International Monetary Fund’s calculations. China, the U.S., Russia, the European Union and India are the largest subsidizers, and these subsidies sharply increased after Russia’s invasion of Ukraine in 2022 disrupted energy markets.

U.N. Secretary-General António Guterres has stressed the importance of transitioning away from fossil fuels, criticizing the extensive profits made by “entrenched interests” in the fossil fuel sector.

African countries also made their view of subsidies clear in the “Nairobi Declaration” at the first Africa Climate Summit in 2023, where leaders called for the elimination of inefficient fossil fuel subsidies and endorsed the idea of a global carbon tax on fossil fuel trade.

The global stocktake highlights the significance of eradicating fossil fuel subsidies to eliminate economic roadblocks that hinder the shift to greener energy sources. However, it’s important to note that the report uses the phrase “unabated fossil fuels.” The word “unabated” has been contentious. It allows room for continued use of fossil fuels, as long as technologies such as carbon capture and storage prevent emissions from entering the atmosphere. But those technologies aren’t yet operating on a wide scale.

Solutions for an equitable transition

Several initiatives have been launched recently to expedite the move away from fossil fuels.

In July 2023, Canada unveiled a strategy to terminate inefficient fossil fuel subsidies, becoming the first G20 nation to pledge a halt to government support for oil and natural gas, with some exceptions.

The European Union is broadening its carbon market to include emissions from buildings and transport, targeting decarbonization across more sectors. Concurrently, the United States’ Inflation Reduction Act commits US$10 billion to clean energy projects and offers $4 billion in tax credits to communities economically affected by the coal industry’s decline.

To help low-income countries build sustainable energy infrastructure, a relatively new financing mechanism called Just Energy Transition Partnerships is gaining interest. It aims to facilitate cooperation, with a group of developed countries helping phase out coal in developing economies that are still reliant on fossil fuels.

South Africa, Indonesia, Senegal and Vietnam have benefited from these partnerships since the first was launched in 2021. The European Union, for instance, has pledged to support Senegal’s shift from fossil fuels to renewable energy. This includes managing the economic fallout, such as potential job losses, from shutting down fossil fuel power plants, while ensuring electricity remains affordable and more widely available.

By COP28, a comprehensive plan to help Senegal aim for a sustainable, low-emissions future should be in place. France, Germany, Canada and various multilateral development banks have promised to provide 2.5 billion Euros (about US$2.68 billion) to increase Senegal’s renewable energy output. The goal is for renewables to account for 40% of Senegal’s energy use by 2030.

To align with the Paris Agreement objectives, we believe global initiatives to reduce fossil fuel dependency and invest in developing nations’ sustainable energy transition are essential. Such endeavors not only champion reducing greenhouse gas emissions but also ensure economic growth in an environmentally conscious manner.

The authors do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.

Frustration with electric utilities is universal today. Whether it’s concerns over high rates, poor service or a combination of both, people are constantly looking for a better answer to the systems that serve them.

In the Nov. 7, 2023, election, voters in Maine had a chance to consider a new model for electricity service that would replace the state’s two widely unpopular private utilities, but they balked in the face of multibillion-dollar cost projections.

This decision took the form of two ballot questions. Question 3 asked whether voters wanted to create a new publicly owned power company, dubbed Pine Tree Power, to take over the existing assets of Maine’s two privately owned utilities. The related Question 1 asked whether consumer-owned electric utilities should have to get public approval before taking on more than US$1 billion in debt. Voters adopted Question 1 and soundly defeated Question 3.

Municipal ownership of utilities is not new: Across the U.S., about 2,000 communities have public power utilities. In Nebraska, all electricity providers are publicly owned.

But private utilities often fight against public takeover attempts – and Maine was no exception. The parent companies of Central Maine Power and Versant Power spent nearly $40 million campaigning against the ballot measures, compared with $1.2 million on the pro-public power side.

At the University of Florida’s Public Utility Research Center, I work with utilities and regulators around the world to assess different ways of structuring power companies. Questions about what kinds of utilities best serve the public have intensified in recent years. As the Maine vote shows, people want different and sometimes competing things from their utility systems.

Three basic structures

There are three basic ownership models for electric utilities. Investor-owned utilities, or IOUs, are owned by private shareholders, who might live next door or halfway around the world. Their stock is publicly traded, and their CEOs have a fiscal responsibility to shareholders as well as to serve their customers.

Municipally owned utilities, often known as munis, are owned locally, generally by the government of the city they serve. Some municipal utilities also serve customers in surrounding areas.

Cooperative utilities are owned entirely by their customers, much like housing or food co-ops. Initially, cooperatives tended to be located in more rural zones. Some of these areas, such as southwest Florida, have grown so rapidly that the term “rural cooperative” no longer applies.

Both munis and cooperatives operate as nonprofits. There is no consistent nationwide link between rates and ownership structure, but it is notable that five of the nine municipal and cooperative utilities in Maine charge less then 15 cents per kilowatt-hour for residential customers, compared with 27 to 30 cents for Central Maine Power and Versant. This may have influenced voters’ perception that a municipal utility could provide power at lower prices.

Municipal utilities do return a portion of their revenues to their investors, but a muni’s investor is the city it serves. According to the American Public Power Association, in 2020, public power utilities returned a median of 6.1% of their revenues to the communities they served. This return allows local governments to keep taxes lower than would otherwise be necessary to provide government services.

These utilities are also regulated in different ways. Investor-owned utilities are regulated by state public utility commissions, which oversee everything from what kinds of facilities to build and where to build them to how to reflect those costs in electricity rates.

Municipally owned and cooperative utilities are typically regulated on a limited basis by state public utility commissions – usually on matters of safety, reliability or the utilities’ impacts on the rest of the grid. Responsibility for municipal utility rates lies with either the city council or an independent local utility board. Cooperative utilities typically set their rates through a board elected by their customers.

Maine’s approach

The structure proposed in Maine was a fascinating hybrid case. Pine Tree Power’s ownership would have closely mirrored that of a municipal utility, governed by a board, but its rates would have been regulated by the Maine Public Utilities Commission. It is unclear what the board’s responsibilities would have been.

Further, since the public utility commission would have been required to set rates according to the actual costs of providing service, it is unclear whether Pine Tree Power would have been allowed to charge rates sufficient to return revenue to the state, similar to what most municipal utilities do.

There was intense debate about Pine Tree Power’s potential benefits. One study showed that shifting from private to public power would produce significant benefits, while another showed significant costs. A third study forecast long-term benefits but short-term costs, primarily from buying out the state’s two private utilities.

In a municipalization, the cost to buy out the private utility strongly influences how much net benefit will result – and it’s not as simple as writing a check for the book value of the assets. Typically, price determination is a quasi-judicial process overseen by an arbitrator.

For example, when Winter Park, Florida, took control of the local assets of its power provider in 2005, the city estimated the value of the physical assets at $15.8 million. The eventual purchase price determined by an arbitrator was just over $42 million. The city also incurred legal and technical support costs. Winter Park issued almost $49 million in bonds to cover all of the costs of the acquisition.

Maine’s cost safeguard

One curious element of the Maine vote that could have future impacts is the voter approval process under Question 1, which was adopted. Typically, when a community municipalizes its electric power, voters would consider an initial referendum authorizing the government to explore the possibility of purchasing the private utility’s assets, and then a second referendum when the costs of the purchase were known.

The second vote would be more specific – something like, “Should the City issue bonds in the amount of $200 million to finalize the purchase of the assets of XYZ Corp. for the express purpose of establishing a municipal utility?”

This approach is expensive to administer, since it requires two votes, and a defeat at either stage can stop the acquisition process. But it also safeguards voters, since it ensures that they have information about how much municipalizing their utility will cost before they vote to approve it.

Cost estimates for buying out Maine’s utilities and creating Pine Tree Power ranged from $5 billion to $13.5 billion, and buyout opponents – including Maine Gov. Janet Mills – strongly emphasized the potential price tag. However, the fact that voters approved Question 1 might actually make a future municipalization vote more likely to pass, since voters now know they will have a safeguard of knowing the purchase price prior to their final approval.

Ultimately, in my view, there is no best model for utility ownership and operation. One strength of private utilities is that they are subject to clear, consistent oversight by professional utility regulators. For their part, municipal and cooperative utilities offer local control and greater flexibility to address local concerns. However, all types of power companies face daunting challenges, including grid cybersecurity, the clean energy transition and hiring and retaining skilled workers.

As I see it, a community’s best strategy is to choose a model that has strengths residents value, and whose weaknesses are less important or can be mitigated in other ways. While Maine voters may not love the system they have, their fear of the unknown was apparently stronger.

Theodore Kury is the Director of Energy Studies at the University of Florida’s Public Utility Research Center, which is sponsored in part by the Florida electric and gas utilities and the Florida Public Service Commission. In 2018, he was principal investigator on a grant from the Jessie Ball duPont Fund to study the value of municipal utilities in a changing marketplace. That work informs portions of this piece. However, the Center maintains sole editorial control of this and any other work.