exp Carbon emissions spiked in 2019_00002001.jpg
US carbon emissions on the rise again
06:24 - Source: CNN
CNN  — 

There may actually be a way to keep the worst of climate change at bay, but it’s going to take a herculean effort, according to a new study published Tuesday in the journal Nature Communications.

Climate change is well underway already, the time to act and limit its human causes is now, many studies have shown. This latest report maps out what it may take to get there.

It posits that if the world was to phase out its “carbon-intensive infrastructure” at the end of its design lifetime starting from the end of 2018, there’s a 64% chance that the planet’s peak temperature can remain below the goal of 1.5 degrees Celsius (2.7 degrees Fahrenheit) above pre-industrial levels. Above that, scientists predict the planet will see even more extreme weather events such as wildfires, droughts, floods, massive animal die offs and food shortages for millions. The planet is already two-thirds of the way there, with global temperatures having warmed about 1 degree Celsius.

To keep the global median temperature within this optimal 1.5 degree-Celsius limit, according to this study, change would have to happen across all sectors, not just in the energy sector. Power plants would need to be replaced, but so would gas and diesel-fueled cars, aircraft, ships and industrial plants. Even cows would have to go – essentially, anything that contributes to global warming.

Under this scenario, infrastructure such as power plants wouldn’t have to be scrapped and replaced with a non-carbon emitting technology – at least, not immediately. The researchers are talking about a “design lifetime.” In the case of power plants, the average lifetime based on historic data, is about 40 years. The average lifetime of a car on the road now is more than 11 years, according to Consumer Reports, but could last for about 200,000 miles, or 15 years, US estimates show. Once they wear out, stop working or die, they’d be replaced with technology or products that do not contribute to climate change.

“It seemed surprising at first that below 1.5 degrees Celsius could still be achieved with all the current infrastructure that is out there. It goes a little against conventional wisdom,” said co-author Chris Smith, a research fellow at the Institute for Climate and Atmospheric Science in the School of Earth and Environment, University of Leeds. “But it actually makes sense in context of the remaining “carbon budget” – basically how much we can emit and still stay under this limit.”

Smith’s study doesn’t determine if this would be politically or economically feasible, but it does show dozens of scenarios that demonstrate the impact certain actions could have on the global mean temperature. The study shows time matters. If the world waits until 2030 to begin to eliminate its carbon-intensive infrastructure, the probability that the world can meet this 1.5 degree C goal is below 50%, even if the rate of fossil fuel retirement was accelerated.

“(The study is) motivation to continue aiming for a zero-carbon world not long after the middle of this century,” Smith said of the research results. “Limiting temperature rise reduces the risks of irreversible damages.” He adds, “the earlier we act, the less expensive the transition will be, and the lower the temperature rise is, the less climate-related damages will cost us.”

In October, a stark report from the UN Intergovernmental Panel on Climate Change said governments around the world must make “rapid, far-reaching and unprecedented changes in all aspects of society” to avoid disastrous levels of global warming. It predicted the planet will reach the crucial threshold of 1.5 degrees Celsius as early as 2030.

The United Nations’ research shows that projected emissions of carbon dioxide from around the world is woefully short of the goals set in the Paris agreement. The current emission targets of all countries would end up creating an average global temperature rise of 3.2 degrees Celsius (5.8 degrees Fahrenheit) by 2100, according to UN research.

Emissions from the power sector, for example, have slowed down globally, although they were on the rise in the United States and that comes after a huge push for power plant development. A 2014 study showed there were more coal-fired power plants built in the decade before the study than in any previous decade. Last August, the Trump administration announced it would loosen restrictions on coal-fired plants. By the US Environmental Protection Agency’s own estimate, the additional pollution will result in up to 1,400 more premature deaths a year as of 2030.

Get CNN Health's weekly newsletter

Sign up here to get The Results Are In with Dr. Sanjay Gupta every Tuesday from the CNN Health team.

“The scenarios that we investigate in this study are really at the extreme optimistic end of what could be done without negative emissions or killing off power plants or cars before their time,” Smith said. “While the solution we propose is technically possible, it still doesn’t look particularly likely. However, I would claim that mapping it out is a good starting point, and consistent with the definition of an infrastructure commitment. It would be interesting to see if, or how, some of these results change with perhaps more real-world assumptions.”