If it was a country, the healthcare sector would be the fifth-largest emitter of greenhouse gases. A new report launched at this year’s Skoll World Forum outlines how to bring down the sector’s emissions profile.

The report, produced by the nongovernmental organization Health Care Without Harm (HCWH) and the global engineering and consulting firm Arup, serves as a road map to decarbonizing the healthcare sector.

Globally, the sector accounts for 4.4% of greenhouse gas emissions, most of which come from burning fossil fuels for everything from powering facilities to transporting supplies. In the U.S., healthcare represents an even greater share of the total carbon footprint, 8.5% of U.S. greenhouse gas emissions.

According to modeling in this new report, without intervention healthcare’s environmental impact will keep growing. In 2014, the sector produced two gigatons of greenhouse gas emissions, and that annual contribution could triple by 2050. Even if countries fulfill their nationally determined contributions to the Paris Agreement, the authors project that healthcare's annual carbon footprint will still increase to over three gigatons by 2050.

The report outlines steps that could put global healthcare emissions on a decreasing trajectory, improving healthcare sustainability and quality.

"Anytime we look at solutions to climate change, we're also going to see potential solutions to human health and environmental health at the same time," said Melissa Bilec, an associate professor in the civil and environmental engineering department at the University of Pittsburgh.

The authors outline three overlapping pathways to decarbonizing the healthcare sector, starting with healthcare operations. In this pathway, healthcare organizations should decarbonize each part of their operations, moving toward zero emissions buildings, infrastructure and healthcare delivery.

The second pathway, the healthcare supply chain, represents about 70% of global healthcare emissions. The links along the supply chain include producing, packaging, transporting, using and disposing of products. The report advocates for healthcare organizations to use their collective purchasing power to encourage decarbonization in these areas.

Decarbonizing the supply chain also requires manufacturers to develop new, reusable products. "Materials need to be non-toxic, reusable, recycled and recyclable, durable, low-carbon, and renewable," the authors write. This kind of innovation can reduce both climate and financial impacts of healthcare organizations. For example, when the Ronald Reagan UCLA Medical Center made the switch to reusable isolation gowns in 2012, they saved over one million dollars in the next three years and 297 tons of waste.

A third pathway for decarbonizing the health sector relies on other areas of society. "That might mean transformations across land use and agriculture, it might be energy, infrastructure, transport and housing," said Sonia Roschnik, an author of the report and international climate policy director at HCWH, at a press briefing. "All of those influence and add to the health sector carbon footprint."

"Basically what we're saying here is to decarbonize, every part of the health sector must follow trajectory to zero," said Josh Karliner, another report author and the international director of program and strategy at HCWH, at the press briefing.

But these suggested pathways are projected to reduce annual emissions to one gigaton, not eliminate them. To achieve zero emissions, the report suggests ways healthcare systems can become more efficient while delivering better care. These actions include goals like wide implementation of telemedicine services and promoting public health by protecting the environment and discouraging meat consumption.

The report also recognizes that low- and middle-income countries still developing their healthcare systems have different responsibilities than high-income countries. High-income countries need to make dramatic cuts to their carbon footprints in the next decade to approach zero emissions by 2050. But low- and middle-income countries can follow a protracted course.

While building up their healthcare infrastructure, low- and middle-income countries can invest in greener healthcare infrastructure instead of building fossil fuel-powered systems. The authors also suggest that international institutions providing financial support to these countries incorporate climate change adaptation strategies in their aid.

If widely implemented, the actions in the report could put a significant dent in the healthcare sector's emissions. "The actions proposed are very much needed," said Kristie Ebi, a professor in the University of Washington's Center for Health and the Global Environment who was not involved in the report. "What I'm missing is how to make it happen. It's particularly complicated within the United States, the way our healthcare sector is organized."

Take decarbonizing hospitals, for example. The report recommends investing in renewable energy, micro grids for backup electricity, and highly efficient cooling, heating and lighting systems. "These changes make sense and in the long run they'll probably save a lot of money," said Ebi. "But where does the initial funding come from?"  

To get that funding, Ebi continued, you need the political will. "And how do you generate political will? How do you tie up actions in other sectors with what's needed in the health sector?"

There's also some uncertainty of how the initiatives in the report could affect other areas of society. "When you take bold action, you have to think about unintended consequences when you're looking at systemic changes," said Bilec, who was also not involved in the report.

"The choices made within the sector could have negative consequences somewhere else," said Ebi. "This is why it's so important to make sure these kinds of activities are connected with other sectors."

The report acknowledges the importance of "cross-sectional collaboration to achieve health equity, climate justice and community resilience." But both Bilec and Ebi would like to see concrete ways to achieve that.

Regardless, "this is an important contribution," said Ebi. "It highlights key issues for sustainability in healthcare and the important contribution reducing emissions in healthcare can make toward achieving the Paris Agreement."