Photos © Oceano Azul Foundation _ André Nobre
Miguel B. Araújo was honoured to be invited by the Oceano Azul Foundation to join a group of three experts in briefing President Emmanuel Macron on critical environmental issues. During this brief meeting, he highlighted the unavoidable connections between the oceans, climate, and biodiversity. He found President Macron to be a sharp and attentive listener, genuinely engaged in understanding the challenges the world faces.
Yet, as global attention is diverted elsewhere, the oceans continue to bear the brunt of climate change. They will keep warming, with excess heat dissipating as kinetic energy—fueling extreme winds—and as intense evaporation, leading to heavy rainfall. Meanwhile, marine biodiversity, already under immense pressure, risks losing its capacity to sequester carbon, a function that currently offsets approximately 25% of annual CO₂ emissions.
Despite these sobering realities, there is hope. The momentum for expanding marine protected areas (MPAs) is growing. These sanctuaries offer a crucial strategy to restore ecosystems, safeguard biodiversity, and enhance the ocean’s ability to regulate climate. Expanding MPAs and ensuring their effective management remain among the most promising ways to mitigate some of the most pressing threats to the planet’s life-support system.
The Message Conveyed:
The ocean as a heat buffer: Covering over 70% of the Earth’s surface, the ocean serves as a vast heat sink, absorbing more than 90% of the excess heat generated by greenhouse gas emissions. This buffering capacity has slowed global warming by moderating temperature extremes and stabilising regional climates through oceanic currents that redistribute heat.
The limits of oceanic heat absorption: Historically, sea surface temperatures have remained relatively stable. However, the ocean’s capacity to absorb heat is reaching its limit, with certain regions warming at an alarming rate—some by nearly half a degree per year. This signals a weakening of its ability to mitigate climate instability, with potentially dramatic consequences.
The ocean as a carbon sink: The ocean plays a pivotal role in global carbon cycling, absorbing approximately 25% of human CO₂ emissions annually. Marine ecosystems, particularly phytoplankton, drive the biological carbon pump, locking carbon in deep waters for centuries. Unfortunately, ocean warming, acidification, and deoxygenation are disrupting these processes, reducing the ocean’s ability to act as an effective carbon sink.
The depths of carbon storage: The ocean holds about 93% of the planet’s carbon, distributed among dissolved inorganic carbon, organic matter, and sediment deposits. However, only around 8% of this is stored in surface waters, with the remaining 92% residing below 200 metres. This deep-sea carbon reservoir is crucial for long-term climate stability.
The perils of deep-sea mining: Deep-sea mining threatens to compromise the ocean’s ability to store carbon by disturbing carbon-rich sediments that have accumulated over millennia. Such disruptions can weaken deep-sea ecosystems, which play a fundamental role in long-term carbon sequestration. Mining operations risk not only destroying these fragile environments but also releasing stored carbon back into the water column, exacerbating climate change.
Research in Araújo Lab
Researchers in the Araújo Lab are actively conducting research on marine conservation and the nexus between climate change and marine ecology. During the conversation with President Macron, Miguel Araújo had the opportunity to mention some of the lab’s ongoing, yet unpublished, research. In particular, he referred to the work led by Shahar Chaikin on the effects of climate change on marine biomass, and the work of Diego Bengochea on the carbon cycle and its relationship with climate change. These studies aim to provide a deeper understanding of how oceanic systems respond to environmental stressors and how conservation strategies can be optimised to mitigate these effects.
The Path Forward
While the scientific evidence is clear, the path forward demands urgent action. Strengthening international commitments to marine protection, enforcing stringent regulations on deep-sea mining, and investing in ocean conservation are non-negotiable steps in addressing these challenges. The ocean remains humanity’s greatest ally in the fight against climate change—provided decisive action is taken to safeguard its integrity.
As the world prepares for the next stage in ocean governance, France and Costa Rica are organising the third UN Conference on Oceans in Nice. The Oceano Azul Foundation is actively supporting this event, just as it did in the previous edition held in Lisbon. This continued commitment reflects the growing recognition of the ocean’s vital role in shaping a sustainable and resilient future.