It’s these significant policy wins in an otherwise bleak landscape that make the work of Lee and his colleagues worthwhile. Citing the ‘basic conflict’ between the industry’s dependence on non-renewable energy and the overwhelming consumer demand for air travel, Lee is realistic about what changes can be made in the short term.
“We’re dependent on liquid fossil fuel for air travel, namely kerosene,” he said. “There’s currently no electric technology that would fly aircraft any decent distance. It’s all about power-to-weight ratio, and the batteries required are simply too heavy.
“Some manufacturers are working on so-called sustainable aviation fuels like liquid hydrogen. They could conceivably power flights, but you’d need completely new aircraft to start with. You’d have to redesign the models themselves and, as we know, that takes many, many years.”
Nowhere is the evidence of those fossil fuels more visible than in the sky above us. Turns out, those seemingly attractive white wisps that streak behind planes tell a surprisingly sinister story about the harm of another pollutant: non-CO2 emissions.
Short for condensation trails, these ‘contrails’ form behind aircraft at cruising altitudes where the atmosphere is cold and humid enough. Essentially clouds made of ice crystals produced by the engine’s soot plus water emissions, contrails can last for many hours.
“These clouds reflect the sun’s radiation back to space, cooling the atmosphere, but they can also trap infrared radiation reflected from the Earth,” explained Lee. “This ultimately warms the atmosphere, as the warming effect exceeds the cooling.”
While this process accounts for nearly double the current global warming effect from historic CO2 emissions, Lee maintains the fundamental problem is still that pesky carbon dioxide. “CO2 is the most pernicious,” he said.
“It’s a molecule that doesn’t go away very quickly, and we keep pumping it into the atmosphere. About 50 per cent of it disappears relatively quickly, as in 30 or so years. The rest hangs around for centuries, and the tail end lasts millennia.”
It’s as mind-boggling as it is sobering. In the absence of technology to physically suck CO2 from the atmosphere, and with air travel at an all-time high (38 million scheduled flights per year at the last count), what more can be done?
One solution is simple yet unpopular. “There’s a philosophical argument that we just don’t cost aviation properly,” said Lee. “If we’re to use our limited resources responsibly, it should cost a lot more than it currently does to fly.”
Logical, certainly. Ethical, without a doubt. Attractive to the aviation industry and us world-weary sun seekers? That’s a harder nut to crack.