Why It’s So Hot - and What That Actually Tells Us About Climate Change

It’s been uncomfortably warm in the UK lately - the kind of muggy, restless heat that lingers long after sunset. But this isn’t just about a few sticky nights. Across Europe, we’ve seen a surge in severe weather: intense wildfires in Greece, deadly floods in Germany and Switzerland, and prolonged, record-breaking heatwaves across Spain, Italy and France. Similarly in the US, the catastrophic flash floods that struck Texas’s Hill Country over the Fourth of July weekend - where the Guadalupe River surged 8 metres within 45 minutes and claimed over 90 lives - are emblematic of how a destabilising climate is reshaping weather extremes, with devastating consequences.

It’s tempting - and common - to reach for these events as evidence to support the urgency of whatever climate policy, disclosure standard or net zero framework we’re focused on. But this post isn’t about that. I don’t want to offer another “this is why [insert regulation acronym here] matters” argument.

Instead, I want to explain why this is happening - in physical terms. Because if we want to respond meaningfully to climate change, we need more than headlines and heatmaps. We need climate literacy: a clearer understanding of how the system works, how emissions connect to weather, and why long-term choices made by governments and businesses really do matter.

A Warmer World is a More Energetic World

The starting point is simple, but profound: the Earth’s climate system is an energy balance. Solar radiation comes in, and longwave (infrared) radiation goes back out into space. Greenhouse gases - especially carbon dioxide, methane and water vapour - trap some of that outgoing energy. They don’t stop energy escaping altogether, but they slow it down, thickening the atmospheric ‘blanket’ around the planet.

This leads to an accumulation of energy in the system. Most of it goes into the oceans, which act as vast heat sinks. Some melts ice. And some of it heats the atmosphere directly, increasing the total amount of heat, moisture and motion in the system. That’s why climate change is not just about gradual warming - it’s about disrupting the dynamics of the entire climate engine.

In a more energetic atmosphere, weather becomes more volatile. The extra heat gives weather systems more fuel. Rainfall becomes heavier. Droughts become deeper. Heatwaves last longer. And extreme events - while always a part of natural variability - become more frequent, more intense, and more destructive.

The catastrophic flash floods in Texas this month, and the searing heat across southern Europe, are stark examples of this playing out in real time.

Why This Summer’s Weather Has Been So Severe

The extremes we’re seeing this summer are the product of several overlapping drivers - all of which are being shaped by climate change:

• The jet stream is weakening and meandering. A warming Arctic reduces the temperature contrast between the poles and the equator. This weakens the jet stream - the high-altitude air current that normally keeps weather systems moving - and causes it to meander more. The result is ‘blocked’ patterns, where high-pressure systems stall over one region (causing prolonged heat), while low-pressure systems linger elsewhere (bringing persistent rain and flooding).

• Dry soils and land feedbacks amplify the heat. When soil dries out, more of the sun’s energy goes into heating the surface rather than evaporating water. That means hotter days, faster drying, and less resilience to future heatwaves - a vicious cycle. These feedbacks are particularly strong in Southern and Central Europe.

• The oceans are unusually warm. The North Atlantic has been hitting record sea surface temperatures. Warm oceans add heat and moisture to the atmosphere, increasing both heatwave intensity and rainfall extremes. They also influence atmospheric circulation in ways that can reinforce blocking patterns. The recent flooding in Texas exemplifies all these points, with scientists attributing its intensity to unusually warm Gulf of Mexico waters - around 2°C above average - fuelled in part by Tropical Storm Barry’s remnant moisture, combined with a stalled weather pattern that released unprecedented levels of rain in a short span.

• Warmer air holds more water. For every 1°C of warming, the atmosphere can hold roughly 7% more moisture. That’s why we’re seeing heavier rainfall events - and why floods are becoming more intense, even when average rainfall doesn’t change dramatically.

Each of these mechanisms is rooted in well-understood physics. What’s new is the frequency and overlap - the way multiple extremes are happening at once, compounding risks and stretching response systems to breaking point.

What This Means for Strategy - and Why Education Matters

I studied climate physics at university, and while I now work on climate strategy and regulation, that grounding continues to shape how I think. Because what we’re dealing with isn’t just a policy challenge or a reputational risk. It’s a deeply physical one.

When companies reduce their emissions, they’re not just ticking compliance boxes - they’re helping to reduce the long-term energy imbalance that drives climatic changes. Every tonne of CO₂ avoided is a small step toward slowing the system down.

But to act meaningfully, we need to understand what we’re responding to. There’s often a gap between strategy and science - between what a business is told to do and why it matters in real physical terms. That gap needs closing.

That’s why climate education matters. Not in the abstract, but as a real enabler of better decision-making. Because the physics underpins everything. And the better we understand it, the more credible, connected and resilient our responses can be.

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