LONDON (Reuters) – Spraying chemicals that overshadow the sun high on Earth to slow global warming could be "remarkably inexpensive", costing about $ 2.25 billion a year over a 15-year period , according to a study by US scientists.
PHOTO PHOTO: The sun's rays shine through the trees in a forest on an autumn morning near Biere, Switzerland, September 26, 2018. REUTERS / Denis Balibouse / File Photo
Some researchers say that the geoengineering technique known as the injection of stratospheric aerosol (SAI) could limit the increase in temperatures that are causing climate change.
Although unproven and hypothetical, this would involve the use of huge tubes, cannons or aircraft specially designed to spray large amounts of sulphate particles into the upper atmosphere layer to act as a reflective barrier against sunlight.
The total costs to launch a hypothetical SAI effort in 15 years would be 3.5 billion dollars, Harvard University scientists said in a report published in the journal Environmental Research Letters, adding that the average annual operating costs would be about 2.25 billion dollars per year in 15 years.
By discounting other deployment methods due to cost and feasibility, the research assumes that a special aircraft can be designed to fly at an altitude of about 20 km and transport a 25-tonne load.
After direct input from several aerospace and engine companies, scientists said they had developed a project that could be suitable and could be ready to be implemented in 15 years, with the goal of reducing the speed of changeovers. half temperature.
The scientists stressed that this is only a hypothetical scenario.
"We do not judge the opportunity of SAI, we simply show that a hypothetical program of deployment that began 15 years ago, although highly uncertain and ambitious, would actually be technically possible from an engineering point of view and would be extraordinarily economical," he says. the report.
There are risks to potential unproven technologies. The scientists said that the SAI could lead to negative consequences such as causing drought or extreme weather conditions in other parts of the world, damaging agricultural crops and potential public health problems and governance.
Furthermore, it does not address the issue of increasing carbon dioxide emissions, the main greenhouse gas responsible for global warming.
Commenting on the study, Phil Williamson at the University of East Anglia said: "Such scenarios are full of problems – and the international agreement to carry out such actions would seem almost impossible to achieve."
Reporting by Nina Chestney; Editing by David Goodman