If doctors today want to fully uphold this responsibility, they need to take an active role in defending their patients from the adverse effects of climate change. Fortunately, by the nature of their profession, physicians are already well-suited to do so.

First, physicians often have close relationships with patients and their families. Not only do we diagnose and treat health risks or damages potentially caused by climate change, but we also have an obligation to advise.

We need to help patients understand that they can help mitigate climate change’s effects by being more conscious in their use of transportation, living in environmentally efficient housing, and eating conscientiously—which means less meat, less wasting food, and using fewer single-use products and packaging. Given our expertise on health, our patients are more likely to trust our advice than that given by a non-physician.

Second, we have to take a look at our own practice. Modern medicine is high-tech, which often means it’s also high in energy and material consumption. This has a price: The energy we use for our diagnostic and therapeutic machinery often comes from carbon dioxide-producing power plants. Single-use products and the abundant packaging of medical products have certainly added to safety and convenience, but we are paying a high environmental price for their production and disposal. Simply relying on energy coming from the power outlet and single-use products that are convenient to use can no longer be taken for granted.

My organization, the World Medical Association (WMA), supports medical practitioners in investigating the environmental footprint of their practices. Advice and help can be drawn from initiatives, such as WMA’s My Green Doctor, a guide by and for doctors to implement environmental friendly practices. This has often the side effect of saving not only natural resources, but also money.

Hospitals have been huge energy wasters in the past. Aiming for an efficient and safe medical process, hospital structures did not necessarily consider the environmental impact of their operations. But high energy costs and growing environmental awareness have begun to change this calculus. The sustainable hospital is no longer wishful thinking: Such medical centers are being built and are running already—with no detriment to medical process and patient care.

Third, medical doctors constitute a powerful constituency. Many of the WMA member associations provide pension funds and some medical communities are big investors. Some medical organizations have commonly decided to divest from high carbon dioxide-producing industries and to boost our environmentally responsible investing. Through this, doctors have sent a message to the market: We value our environment more than short-term returns on investments.

But our engagement must not stop there. Medical leaders must talk to politicians about climate change. Since the 2009 UN climate conference in Copenhagen, we’ve pressed legislators to consider more seriously the health effects of climate change. By talking about the suffering our patients endure and could continue to endure, we are adding a human dimension to the already dire economic predictions of climate models.

Reversing climate change could be the greatest health accomplishment of the 21st century. If doctors want to play a part, we need to develop intelligent solutions that respect the health of both individuals and our planet.

Leonid Eidelman is the president of the World Medical Association.