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How conversations over coffee can spark climate discoveries

 As a distributed research centre, NCEO brings together over 150 experts from renowned UK universities and institutions. We’re eager to share their ground-breaking work and experiences—not just to highlight the science, but to spark though-provoking conversations that challenge research. 

Prof Richard Allan’s recent blog, originally published by the University of Reading, reflects on a casual conversation with NCEO colleague Prof Chris Merchant that led to new insights into Earth’s growing energy imbalance — and what that means for our warming oceans. 

Here’s a summary of their fascinating findings — and a reminder that sometimes the best ideas really do start with a coffee. 

Reconciling Earth’s Growing Energy Imbalance with Ocean Warming 

What started as a light-hearted chat over coffee quickly turned into a research project tackling imperative climate science questions. This was prompted by the extraordinary global warmth observed in 2023 and 2024, they set out to investigate how the Earth’s energy imbalance — the difference between incoming and outgoing energy — is changing, and how this links to record-breaking ocean temperatures. 

Figure 1 – A graph showing increases in Earth’s net energy imbalance (red) since 2000 are mostly explained by increases in absorbed shortwave radiation (dark blue) over the ocean (light blue) but not for clear-sky conditions (dotted). See Allan & Merchant (2025) for details. 

What did they uncover? 

The planet is heating up because more energy is arriving from the Sun than is leaving back into space. Over the past 20 years, this heating rate has doubled. 

Using satellite records and climate data, their analysis showed this growing energy imbalance is largely driven by increasing amounts of sunlight being absorbed over the oceans — especially in cloudy regions where changes to cloud cover is reducing how much sunlight is reflected back to space. This process is sometimes called the Earth’s ‘Dirty Mirror’ effect. These cloud changes could be linked to cleaner air, potentially due the reduced aerosol pollution from shipping and industrial activity, however, it could also be a response to a warming ocean breaking up reflective low-level clouds. Both processes may be amplifying global warming. 

Why is this significant? 

Their work helps explain why the ocean’s surface warmed so dramatically between 2022 and 2023 (the equivalent to a decade’s worth of typical warming in just a single year). This warming could have been exacerbated not only by heat entering the surface ocean but also by changes to how heat is moving within the ocean itself — with less heat being stored in deeper layers and more being returned to the surface. 

Figure 2 – Schematic of energy entering the ocean upper layers for (a) climatological conditions and plausible scenarios for the large warming period 2022-23 (b-c). See Allan & Merchant (2025) for details. 

Understanding these processes further is vital for predicting the future pace of climate change, particularly as the world edges closer to — and likely beyond — the 1.5°C global warming threshold. 

A call for community conversations 

This research highlights the value of curiosity-driven conversations and collaborative thinking — something we’re proud to foster within the NCEO community. Whether it’s over coffee, in meetings, or through informal chats with colleagues, never underestimate where a good question (or a slightly wild idea!) might lead. 

Read the Richard Allan’s Full Blog Here 

Papers that came of the coffee: 
Allan, R.P. & Merchant, C.J., 2025. Reconciling Earth’s growing energy imbalance with ocean warming. Environmental Research Letters, 20, 044002. Available at: https://doi.org/10.1088/1748-9326/adb448 

Merchant, C.J., et al., 2025. Quantifying the acceleration of multidecadal global sea surface warming driven by Earth’s energy imbalance. Environmental Research Letters, 20, 024037. Available at: https://doi.org/10.1088/1748-9326/adaa8a