The glass is already half full

The glass is already half full | Delfino Barboza

When I first came across the data on global oil extraction, the numbers felt almost poetic in their symmetry. Roughly half of the world’s recoverable oil,  around 1.36 trillion barrels,  has already been extracted since the mid-nineteenth century. What remains,  an estimated 1.5 to 1.6 trillion barrels, depending on the source,  stands as both a testament to human ingenuity and a sobering reminder of our dependence on finite resources.

I see this halfway point not as a cliff edge, but as a crossroads. The world’s total recoverable oil is estimated at about 2.9 trillion barrels, meaning that humanity has already consumed nearly 47 per cent of what is economically and technically viable to extract. This is a pivotal figure. It suggests that the “easy oil”,  the vast, pressurised fields that once gushed forth with minimal effort,  is largely gone. What remains lies deeper, heavier, more carbon-intensive, and technologically demanding to recover.

This technical reality also speaks to economics. As extraction becomes costlier, energy return on investment (EROI), the ratio of energy produced to energy spent, declines. In the 1930s, oil’s EROI was close to 100:1; today, it hovers around 15:1 globally and often below 10:1 for unconventional sources such as tar sands. This means we must invest increasingly more energy and capital to produce each barrel, a diminishing return that questions oil’s long-term viability as the cornerstone of civilisation.

But there’s another way to look at the glass. The half that remains represents time, a precious interval in which we can transition towards sustainable systems. The world currently consumes around 100 million barrels per day, translating to more than 35 billion barrels per year. At this rate, even if production holds steady, the remaining recoverable oil could last roughly 40 to 50 years. That is not eternity, but it is enough time,  if we act decisively,  to reshape our energy infrastructure.

Technological progress gives me cautious optimism. Renewable energy capacity is expanding faster than ever before. The International Energy Agency projects that solar power alone will overtake coal by 2027, marking a symbolic shift in global energy dominance. Electrification, storage innovation, and hydrogen technologies are maturing, while policy frameworks such as the EU Green Deal and the UN’s Sustainable Development Goal 13 (Climate Action) are guiding a global agenda towards decarbonisation.

Yes, the glass is half empty if we only count barrels. But I prefer to see it as half full,  filled with possibility, foresight, and the undeniable intelligence of a species that can still choose to evolve. The oil that remains is both a resource and a warning: it can either fuel the inertia of the past or the transformation of the future.

Our responsibility now is not merely to measure what’s left in the ground, but to redefine what we pour into the world. The era of oil may be half over, but the age of renewal has only just begun.