Those concerned with the health our fragile planet have seen major developments recently. Last month’s Papal Encyclical demonstrated the moral courage of a pope who “gets it” that climate change is real, and disproportionately endangers the poor and underprivileged.

The Maine Chapter of Physicians for Social Responsibility released an update to “Death by Degrees: the Health Crisis of Climate Change in Maine,” documenting many aspects of how climate change already has affected the health of Maine residents in adverse ways. These include increases in tick- and mosquito-borne threats, such as Lyme disease and West Nile Virus with the northward spread of these species; weather extremes leading to heat stroke and other illnesses; respiratory disorders because of air pollution and allergens, and mental health problems including PTSD, depression and anxiety as more people are affected by the climate changes.

All Maine legislators will receive a copy of “Death by Degrees,” and we urge them to consider the actions Maine can take as a state, including development of a Maine Clean Power Plan emphasizing renewable energy sources and increased energy efficiency.

Also recently, a special issue of the Lancet, UK’s most prestigious medical journal, echoes and amplifies the stark warning of a 2009 Lancet Commission report, based on more than a decade of strong peer-reviewed scientific evidence: “Climate change is the biggest global health threat of the 21st century.”

This 2015 commission update moves far beyond simply enumerating the greatest direct and indirect health threats posed by weather extremes, crop failures, forced migrations, epidemics and the poisoning of our air and water. It makes a persuasive case for urgent coordinated global action. Despite acknowledging the enormous challenges, the Lancet issue sounds a note of optimism: “Tackling climate change could be the greatest global health opportunity of the 21st century.”

Its authors have wisely focused primarily on the threats to human health, as they recognize that “public concerns about undernutrition and food insecurity have the potential to accelerate political action in ways that attention to carbon dioxide emissions alone do not.”

The extensively documented 46-page report describes in detail nine recommended actions governments must implement vigorously during the next decades to slow or reverse the ominous changes to which human activities unquestionably contribute. Some key strategies are listed below:

• Rapidly expanding access to renewable energy sources and technologies in emerging and low-income countries, enabling a transition away from dependence on fossil fuels.

• Ensuring an eventual phase-out of burning coal and other fossil fuels to protect against respiratory and cardiac illnesses and to help arrest warming of the oceans and atmosphere.

• Establishing the framework for a strong, predictable and international carbon pricing mechanism (essentially a “carbon tax”) to disincentivize creation of greenhouse gases, which reflect back and trap heat.

• Scaling up finances for the development of climate-resistant health systems. The Lancet Commission urges shifting the enormous sums now devoted to extracting and burning fossil fuels to investment in solar, wind and other renewable energy technologies. Energy self-sufficiency is crucially important for hospitals and health facilities in Africa and other Third World locations with unreliable or absent power supplies. The authors emphasize that the needed financial and technical resources will be found if the sufficient political will to act can be generated.

• Facilitating cooperation among governments and health ministries throughout the world to address the threats to human health. The report urges health professionals to take the lead in addressing the enormous obstacle posed by widespread unawareness and/or denial of the realities of climate change and their multiple (and often malignantly additive) adverse health aspects

Close collaboration in the development the updated Lancet Commission report, between the University College London Institute for Global Health and Tsinghua University in China, is an exemplary model for linkages between universities and research centers throughout the world. Such collaboration must rely on a multidisciplinary approach among governmental leaders, political and environmental scientists, geographers, engineers, economists and many others.

A central message of the Lancet Commission’s 2015 report is that the severity of the health impacts of climate change creates a moral imperative to act now when the admittedly enormous costs of mitigation will be far less than waiting until greater threats compel progressively more expensive and less effective crisis measures.

James H. Maier, M.D., of Scarborough, is a board member of Physicians for Social Responsibility, Maine Chapter.