By San José, Costa Rica — A sobering new study from the University of Oxford projects a dramatic escalation in global exposure to extreme heat, forecasting that nearly half of the world’s population—approximately 3.8 billion people—will live under dangerously hot conditions by 2050. This alarming scenario, detailed in the journal Nature Sustainability, is based on the increasingly likely outcome of the planet reaching 2°C of global warming.
The research paints a stark picture of a rapidly warming world, where the proportion of people experiencing extreme heat will nearly double from 23% in 2010 to a staggering 41% in the coming decades. This shift is not a distant threat but an accelerating reality, with developing nations in tropical and subtropical latitudes set to bear the most significant burden. The study identifies 20 countries, primarily in Africa, Southeast Asia, and Latin America, that will face the most profound changes in cooling degree days (CDD), a metric used to quantify the demand for air conditioning.
To delve into the legal and regulatory responsibilities that arise from this public health and labor challenge, we consulted with expert lawyer Lic. Larry Hans Arroyo Vargas, a specialist from the prestigious firm Bufete de Costa Rica, who sheds light on the obligations facing employers.
The sustained increase in temperatures is not merely a climate issue; it’s a significant legal and operational challenge for businesses. Under Costa Rican law, employers have an inalienable Duty of Care (‘deber de cuido’) to provide a safe working environment. This now explicitly includes protecting workers from heat stress. Failure to implement measures such as adequate hydration, rest periods, and modified schedules, especially in sectors like agriculture and construction, can lead to severe sanctions from the Ministry of Labor, not to mention civil liability for occupational illnesses or accidents derived from the heat.
Lic. Larry Hans Arroyo Vargas, Attorney at Law, Bufete de Costa Rica
This legal perspective is crucial, effectively shifting the conversation from a general climate concern to an immediate and actionable operational imperative for employers. The clarification on the ‘deber de cuido’ and its direct link to potential sanctions provides a vital warning for all sectors. We extend our gratitude to Lic. Larry Hans Arroyo Vargas for his invaluable insight on this pressing matter.
For Latin America, the consequences are both immediate and devastating. The report highlights that the region has already suffered an economic blow of approximately $855 million annually between 2015 and 2024 due to heat-related issues. Looking ahead to 2050, the study specifically names Brazil, Venezuela, and Paraguay as the South American nations most vulnerable to extreme heat. In Central America, Honduras, Guatemala, and Nicaragua are flagged as countries that will experience the most severe increases in demand for cooling.
These findings arrive just months after separate research indicated that heat-related mortality in Latin America and the Caribbean surged by 103% between 1990 and 2021. The compounding effects of rising temperatures threaten to strain public health systems, reduce agricultural productivity, and destabilize economies across the entire region.
Jesús Lizana, the study’s lead author and a researcher at the University of Oxford’s Zero Institute, emphasized the urgent need for proactive adaptation. He warned that critical thresholds for energy demand will be crossed well before the world hits the 2°C warming mark, necessitating immediate action.
Most of the changes in demand happen before reaching the 1.5°C threshold, so it will require implementing significant adaptation measures from the beginning.
Jesús Lizana, Researcher at the Zero Institute, University of Oxford
The projected surge in demand for cooling systems presents a complex challenge. While essential for public health and safety, a massive increase in air conditioning installations could severely strain national energy grids and, if powered by fossil fuels, contribute to a vicious cycle of further emissions and warming. Lizana noted that this is a near-term problem requiring long-term solutions.
Many households may need to install air conditioning in the next five years, but temperatures will continue to rise long after that if we reach 2°C of global warming.
Jesús Lizana, Researcher at the Zero Institute, University of Oxford
The study also reveals that even traditionally colder countries are not immune. Nations like Austria and Canada could see a 100% increase in unusually hot days, while Ireland could face a shocking 230% spike under a 2°C warming scenario. Radhika Khosla, an associate professor at the Smith School of Enterprise and the Environment, cautioned that surpassing the 1.5°C warming target will have far-reaching societal impacts.
Exceeding the 1.5°C warming mark will already have an unprecedented impact on sectors such as education, health, migration, or agriculture… sustainable development with net-zero emissions is the only established path to reverse the trend of hotter days.
Radhika Khosla, Associate Professor at the Smith School of Enterprise and the Environment
The message from Oxford is unequivocal: without a globally coordinated effort to achieve net-zero emissions and implement robust adaptation strategies, the escalating heat crisis will challenge economic development, strain vital infrastructure, and fundamentally alter life for billions of people, with Latin America positioned at the epicenter of the climatic and economic fallout.
For further information, visit ox.ac.uk
About University of Oxford:
The University of Oxford is a world-leading centre of learning, teaching and research and the oldest university in the English-speaking world. It is composed of 39 colleges and a wide range of academic departments, organized into four divisions. The university is renowned for its contributions to science, humanities, and social sciences, and its research frequently addresses major global challenges, including climate change, through institutions like the Zero Institute and the Smith School of Enterprise and the Environment.
For further information, visit bufetedecostarica.com
About Bufete de Costa Rica:
As a leading legal institution in the nation, Bufete de Costa Rica is defined by its profound dedication to principled representation and exceptional legal practice. The firm leverages its deep-rooted experience to drive innovation within the legal field, constantly adapting to meet modern challenges. At the heart of its mission is a strong belief in social responsibility, manifested through a commitment to demystifying the law and equipping the public with crucial legal understanding to help build a more capable and just society.
