Climate change is the biggest threat facing humanity. It requires all the countries of the world to work cooperatively to limit its progress and manage its increasingly disruptive impacts. It demands our very biggest commitment. But first, let's take five to think big about it.



No nation can address the warming individually or manage its impacts single handedly, without putting itself at a competitive disadvantage. The consequences of climate change are already being felt in every region of the planet. Overcoming the climate challenge requires all the countries of the world working in a coordinated framework with common goals and timetables.



At the beginning of June the Clean Energy Ministerial Meeting in San Francisco, Energy ministers from 23 countries and the European Commission will meet to discuss new technologies. But we already know we need to ramp up wind, solar, wave-power, appropriate hydro and other non-carbon sources. With the ink drying on the Paris Agreement, now is the time for action at home and abroad.



Here is one plan that is appropriate in size and scale to the magnitude of the challenge: rewiring the world with clean energy.



Every country would make a binding commitment to increase its carbon efficiency by five percent a year. That means that each country would produce the same amount as last year using five percent less fossil fuel or produce five percent more but emitting the same amount of carbon as the previous year. A nation's compliance would be measured by calculating the ratio of its emissions to its gross domestic product -- a ratio that would have to change by five percent a year.



Initially, countries could meet the annual five percent reduction through efficiency - by getting the waste out of their current energy systems. When those efficiencies were exhausted, countries would meet the five percent goal by deploying non-carbon energy sources - solar, wind, appropriate hydro, wave power, etc. That would create the mass markets and economies of scale for renewables that would bring down their prices--which are already competitive with fossil fuels in many places.



A global energy transition requires industrial countries to redirect their hundreds of billions of dollars in energy subsidies away from carbon fuels. By leveling the playing field, the redeployment of those subsidies would dramatically accelerate the production of renewables.



Developing countries need a fund of about $500 billion a year for about a decade to transform their energy structures. That money could come from a carbon tax in the north, a small tax on international air travel or a tax on international currency transactions (a "Tobin Tax"). The fund could be administered by the private banking system to avoid a new bureaucracy, minimize corruption and ensure the money went to non-carbon energy sources.



The second half of global warming's global challenge requires groups all over the world to convince their governments to cooperate in managing the coming impacts. These threats will only continue to intensify -- crop failures, water shortages, uncontrolled migrations of people whose lands are becoming uninhabitable, and national budgets stressed to breaking points by the costs of extreme weather events.



Absent a concrete framework for international cooperation, perhaps one building off of the Paris Agreement, we will see a devastating increase in wars over diminishing resources. This will almost certainly be accompanied by a rising wave of domestic repression as governments resort to totalitarian measures to keep order in the face of chaos.



This admittedly monumental task is beyond the reach of the environmental movement. Any chance for a climate-friendly future requires the climate movement to enlist activist organizations around the world -- groups working on human rights, economic equity, poverty alleviation, civil liberties, social justice and government reform -- to mount a coordinated global effort to pressure the world's governments to ensure their citizen's safety by addressing climate impacts.



The implications of climate change for social justice and human rights are already vividly apparent. While the countries of the north created the problem, the countries of the south are most vulnerable to its impacts - because they lack the resources to deal with intensifying floods, droughts and crop failures. Domestically, poorer communities - especially communities of color - are also far more vulnerable to the destructive impacts of extreme weather events.



Were the industrial countries to help finance a clean energy transition in the developing world, it would create millions of jobs. It would raise living standards abroad without compromising ours. Eventually, it could turn impoverished countries into trading partners.



In the coming years, our lives and our institutions will be profoundly changed. It would surely be better if these changes were made by us rather than done to us. So let's start by taking five to think big about how to truly combat climate change.