Dear World Leaders,

We write to you today with a profound sense of alarm and a pressing need for urgent action. The events unfolding in the Antarctic are a stark harbinger of the dangers posed by climate change, and they demand an immediate and concerted global response.

The scientific evidence is irrefutable: the record-breaking decline of Antarctic sea ice in 2023 has set in motion a cascade of consequences that threaten to destabilize the delicate balance of our planet’s climate system. This is no longer a distant threat, but a present crisis that requires your unwavering attention and resolute leadership.

The Antarctic, often referred to as the Earth’s “refrigerator,” has long been a critical regulator of global climate patterns. Its expansive sea ice cover has acted as a vast insulating blanket, moderating the exchange of heat and moisture between the ocean and atmosphere. However, this once-reliable mechanism has now been fundamentally disrupted.

In 2023, the Antarctic experienced a staggering 80% reduction in sea ice cover in key regions, including the Weddell, Bellingshausen, and Ross Seas. This unprecedented loss has unleashed a profound transformation in the dynamics of air-sea interaction, with far-reaching implications that extend far beyond the frozen continent.

The paper, published in this month’s journal Nature, reveals that this dramatic sea ice retreat has triggered an alarming surge in ocean heat loss to the atmosphere. In the most severely affected areas, the ocean is now shedding heat at more than twice the rate observed in previous decades. This sudden and intense heat transfer is a clear and present danger, one that demands your immediate attention.

The consequences of this heat flux are manifold and deeply troubling. We have observed a marked increase in the frequency and intensity of storm systems over the newly exposed ocean surfaces, with the number of high-wind events increasing by up to 7 days per month in some regions. These powerful storms have the potential to disrupt weather patterns far beyond the Antarctic, impacting food and water security, infrastructure, and the livelihoods of communities across the globe.

Furthermore, the enhanced ocean heat loss is driving a fundamental shift in the formation of dense water masses, the building blocks of the Southern Ocean’s critical overturning circulation. We have detected a striking increase in the production of the densest water types, with the surface flux contribution to high-density water formation exceeding previous records by more than a factor of 10 in some areas.

This dramatic densification of the ocean’s surface layers has profound implications for the broader climate system. The modified water masses formed in these newly ice-free regions have the potential to influence the properties and circulation of the deep, abyssal waters that drive global ocean currents. Disruptions to this delicate balance could reverberate throughout the world’s oceans, altering patterns of heat and carbon transport with cascading effects on regional and global climate.

The stakes could not be higher. The Antarctic sea ice loss is not simply an isolated phenomenon, but a harbinger of the catastrophic changes that await us if we fail to act decisively. The impacts extend far beyond the Southern Ocean, with the potential to disrupt tropical climate patterns and influence weather and climate in the Northern Hemisphere as well.

We must not underestimate the gravity of this situation. The 2023 Antarctic sea ice decline represents a fundamental shift in the state of the Earth’s climate system, one that threatens to unleash a cascade of consequences that could unravel the fragile balance upon which human civilization and the natural world depend.

Your Excellencies, the time for action is now. We call upon you, the leaders of the world’s nations, to heed this clarion call and respond with the urgency and resolve that this crisis demands. Failure to do so will condemn us all to a future of escalating climate chaos, with devastating impacts on the lives and livelihoods of billions of people.

The path forward is clear, but it requires your unwavering commitment and bold leadership. We implore you to take the following steps without delay:

1. Declare a global climate emergency:

Acknowledge the severity of the crisis unfolding in the Antarctic and commit your nations to a coordinated, worldwide effort to address the threat of climate change. This declaration must be backed by concrete, measurable actions and a timeline for implementation.

2. Accelerate the transition to renewable energy:

Implement policies and incentives that rapidly accelerate the deployment of renewable energy sources, such as solar, wind, and geothermal power, across all sectors of your economies. Fossil fuel subsidies must be phased out, and a price on carbon emissions must be established to drive the necessary shift in energy infrastructure and consumer behavior.

3. Invest in climate adaptation and resilience:

Allocate significant resources to strengthening the resilience of communities, infrastructure, and ecosystems to the impacts of climate change. This includes improving early warning systems, enhancing disaster preparedness, and supporting the development of climate-smart agriculture and water management practices.

4. Protect and restore natural carbon sinks:

Prioritize the conservation and restoration of forests, wetlands, and other natural ecosystems that serve as vital carbon sinks. Halt deforestation and promote sustainable land-use practices that enhance the ability of these ecosystems to sequester and store atmospheric carbon.

5. Enhance international cooperation and climate finance:

Strengthen global cooperation and coordination on climate action, including through the United Nations Framework Convention on Climate Change (UNFCCC) and other multilateral frameworks. Fulfill and exceed the commitments made under the Paris Agreement, and significantly increase the provision of climate finance to support mitigation and adaptation efforts in developing countries.

6. Invest in climate research and innovation:

Allocate significant resources to expand and deepen our scientific understanding of the complex dynamics of the Earth’s climate system, including the interactions between the atmosphere, oceans, and cryosphere. Foster the development of innovative technologies and solutions that can help us mitigate and adapt to the impacts of climate change.

Your Excellencies, the future of our planet and the well-being of generations to come hang in the balance. The events unfolding in the Antarctic are a stark warning that the climate crisis is no longer a distant threat, but a clear and present danger that requires your immediate and decisive action.

We urge you to heed this call and take the necessary steps to address the peril of Antarctic sea ice loss and the broader climate emergency. The world is watching, and history will judge us all by the actions we take in this critical moment.

Sincerely,

Us, the Citzens of the World