#todayinsight: From Taboo to Pragmatism: The Rising Tide of Geoengineering in the Fight Against Global Warming!

Ten years ago almost no scientist dared to speak openly about geoengineering. The subject was considered as going too much, crossing the red line. But as the earth is suffering from global warming, and the attempts to replace renewable energy energy has fallen from its targets. Thermal geoengineering is gaining more and more attention. 

As the sun shines to the planet earth, about 70 percent of it is absorbed. Around 30 percent is reflected by the clouds and ices. This is called the Albedo ratio! 

Part of the absorbed energy is eventually emitted from the earth surface. But the greenhouse gasses would not allow all the re-emitted energy to reach space. Greenhouse gasses absorb infrared waves and would not let the earth to further cool down. The most important greenhouse gas is carbon dioxide. Back in the times of industrial revolution, the atmosphere contained 280 parts of carbon dioxide in one million parts. The ratio has risen to 417 last year. Alongside this, last year was the hottest year since the industrial revolution.

While developing the green economy and adapting renewable energy attempts to reduce global warming, lowering the production of greenhouse gasses. Thermal Geoengineering provides the solutions to increase the earth’s Albedo ratio. More sunlight is reflected from earth and this would offset the warming effect of greenhouse gasses!

There is natural proof of concept. The planet earth Albedo ratio can be temporarily altered by volcanic eruptions, which adds specific particles and gasses into the atmosphere. Sulfur oxide is particularly important. It combines with water and forms sulfur aerosols, which reflects the sunlight perfectly. In 1991 mount Pinatubo in the Philippines put 15 million tonnes of sulfur into the atmosphere. The earth Albedo ratio increased temporarily and that was enough to lower the earth temperature by 0.5 centigrades for over a year.

Burning fossil fuels produces superoxide, and this has had a minor cooling effect. But fossil fuels produce much more carbon dioxide compared to sulfur dioxide. And they are mostly trapped in the lower section of the atmosphere with minor reflecting effects. And the gasses are toxic as well and cause hundreds of thousands of deaths each year.

The basic concept of geoengineering is to annually inject a few millions of sulfur oxide, or calcium carbonate or even powers of aluminum or synthetic diamond into the stratosphere, which begins 20 km from the surface. This would sufficiently raise the planet earth Albedo ratio and cancel out the warming effect of greenhouse gasses. The annual cost is a few tens of billion dollars, the annual cost of decarbonizing the global economy on the other hand, runs into trillions of dollars.

The skepticism is still strong. In 2021, an experimental test of delivery mechanisms of sulfur particles into the stratosphere was canceled thanks to the lobbying from environmental activists from Sweden. In 2022, an American Startup, Make Sunset, carried out an unauthorized experiment in northern mexico. It released some small amounts of particles to study how it reflects the sunlight. After informing, the Mexican government banned anything similar from happening again.

There are numerous arguments against thermal geoengineering, they say that it may unintentionally ruin the Ozone layer causing much more harm than good. As a result of greenhouse gasses, the sea water has become more acidic than ever before and geoengineering does nothing about it. Others argue that it provides a cheap solution, and makes countries abandon the sustainable solution which is adapting to renewable sources of energy. 

Anyway as the earth gets warmer, geoengineering becomes a pragmatic solution. It can provide us with a temporary solution and buy more time as we move toward a green economy.

Source: Economist