International leadership based on sound science can lead to great results. For proof, we need only “look up, look way up,” as one of my colleagues at CBC used to say. The ozone layer is no longer shrinking.

Starting in the 1970s, scientists observed a connection between our use of chlorofluorocarbons, or CFCs, and a weakening of the ozone layer in the stratosphere. High above Earth, ultraviolet light breaks chlorine off the CFC molecule, and chlorine is a potent scavenger of ozone. Stratospheric ozone absorbs ultraviolet radiation, protecting us from the sun’s rays like a giant pair of sunglasses.

CFCs were once used in products ranging from aerosol spray cans to refrigerators. As more of the chemicals were dumped into the air, they began to destroy the ozone layer, creating the potential for dramatic increases in skin cancers and damage to the phytoplankton that form the base of life.

In September 1987, world leaders signed the Montreal Protocol on Substances that Deplete the Ozone Layer. Now, a report written and reviewed by 300 scientists from around the world concludes that phasing out production and consumption of ozone-depleting substances under the Montreal Protocol “has protected the stratospheric ozone layer from much higher levels of depletion.”

It’s not a complete turn-around, but it is good news. The scientists found that global ozone and ozone in the Arctic and Antarctic regions are no longer decreasing but they are not yet increasing either. They also write that “the ozone layer outside the Polar regions is projected to recover to its pre-1980 levels some time before the middle of this century.”

UN Environment Programme executive director Achim Steiner noted that, without the agreement, atmospheric levels of ozone-depleting substances could have increased tenfold, leading to “up to 20 million more cases of skin cancer and 130 million more cases of eye cataracts, not to speak of damage to human immune systems, wildlife and agriculture.”

Interestingly, the scientists and world leaders who worked to protect us from ozone depletion faced many of the same pressures that those working to protect us from climate change now encounter. CFC manufacturers claimed that the science on the dangers of CFCs was “rubbish” and that phasing out CFCs would cost trillions of dollars and would destroy the industry.

As Naomi Oreskes writes in her excellent book Merchants of Doubt, many of the same “experts” show up in the campaigns industry has waged against the science regarding the impacts of tobacco, CFCs, acid rain, and climate change.

If we can succeed in tackling the ozone problem, despite attacks from industry, why is it so difficult to resolve an even greater threat to life on the planet, climate change? One of the scientists who won a Nobel Prize for chemistry in 1995 for his work on the ozone layer has an explanation. Sherwood Rowland says that “arguing which propellant to use was rather trivial to society. One could replace CFCs and still use existing technology. This is quite different from having fossil fuels as our primary energy source for the whole world.”

In other words, the stakes are higher – for industry and society. In many cases, CFCs could be replaced by something as simple and non-polluting as compressed air. And despite the claims of chemical manufacturers, phasing out CFCs did not bankrupt the industry, because these chemicals were only one product among many that the companies produced.

Although some energy companies are working on clean-energy technology, their massive profits come mainly from exploiting ever-dwindling supplies of fossil fuels. And pretty much everyone in the world relies on fossil fuels to some extent. The good news is that in the past two years total worldwide investments in renewable electricity generation were greater than total investments in fossil fuel–based electrical capacity.

The solutions exist, but it will take a lot of effort and political will to make the shift. If we do it right, it will have enormous benefits for human health and economies. But don’t expect the most profitable industry in the history of the universe to get on-board any time soon.

It’s up to all of us to demand change. The Montreal Protocol shows that progress is possible, but we must listen to reason rather than the claims of those who put profits before people.

Dr. David Suzuki is a scientist, broadcaster, author, and chair of the David Suzuki Foundation and Dr. Faisal Moola is the Director of Science at the David Suzuki Foundation.

Learn more at www.davidsuzuki.org.