Climate change is the greatest threat to public health worldwide and doctors must step up to help mitigate it, according to a leading advocate speaking at the annual Canadian Medical Association (CMA) meeting in Vancouver on Monday.Dr. James Orbinski, a former top official with the medical charity Doctors Without Borders/Médecins Sans Frontières (MSF), who is now an an associate professor of Medicine at the University of Toronto, urged physicians to \u0022step up and step out\u0022 in the fight against climate change as part of their duties to create \u0022health-in-all\u0022 policies.\u0022We\u0026#039;re not separate from our biosphere, or our planet,\u0022 Orbinski told the audience of 600. \u0022We can\u0026#039;t possibly live, survive, and thrive without our biosphere. It affects us and we affect it.\u0022\u0022Climate change is very much of our own making...but as doctors, we have a vital responsibility to urge the development of a health-in-all-policies approach,\u0022 he said.The summit is taking place following extreme weather events and other environmental catastrophes throughout Canada, from wildfires in Fort McMurray to a massive oil spill in Saskatchewan.The Vancouver Sun reports on Orbinski\u0026#039;s comments:Droughts, fires like the one in Fort McMurray in May, floods, food security and infectious diseases are all linked to climate change.Mental health problems and respiratory ailments from air pollution as well as rising rates of infectious diseases like West Nile virus and Lyme disease are also\u0026nbsp;some of the consequences of climate change.He also noted that Canada\u0026#039;s yearly rate of warming is twice the global pace, which means the effects of climate change will increase as time goes on, absent a concerted effort to reduce greenhouse gases.\u0022The implications are utterly profound,\u0022 Orbinski said.\u0022People go to war over water, food and territory, and when you cannot feed your children, you will do anything, even if it means going to war. This is the reality of climate change.\u0022CMA president Dr. Cindy Forbes said the organization would attempt to create an action plan. \u0022I appreciated greatly Dr. Orbinski\u0026#039;s call to action, and I agree as a nation and as a planet we cannot ignore climate change,\u0022 she said.