As the world’s leaders prepared to hold a summit on climate change at the United Nations last week, 400,000 protestors marched through the streets of New York City demanding actions – not just words.

And their call was backed up by the latest scientific analyses.

Researchers at the National Oceanic and Atmospheric Administration announced that this summer — the months of June, July and August — was the hottest on record and that 2014 was on a trajectory to be the hottest year ever.

In addition, a report conducted by the organization Climate Central examined the impact that global warming-induced rises in sea levels would have on nations which faced the gravest risks from significant flooding.  Climate scientists expect flooding to increase as global warming melts snow and ice in the Arctic and Antarctic thus expanding the volume of oceans.

According to the report, about 2.5 percent of the world’s population — about 177 million people — live in areas that will be vulnerable to chronic flooding as a result of climate change.

It is an undisputed fact that the world is getting hotter.  The fight over policy begins with whether the warming planet is the result, or largely the result, of human activities.

There is ample evidence that the world is pumping carbon dioxide into the atmosphere at unprecedented levels.  The world’s experts on climate change have concluded that sea levels are increasing at the fastest rate in 2,000 years.  Concentrations of carbon dioxide in the atmosphere have reached “levels unprecedented in at least the last 800,000 years” (or before modern humans evolved).  Most importantly, the experts say, “human influence on the climate system is clear” and “continued emissions of greenhouse gases will cause further warming.”

Of course,there is substantial uncertainty about the future of carbon emissions,global warming and sea levels.  But the overall view is that human activity is a major factor in driving the increased temperature of the planet.

So why do hundreds of thousands have to organize a march?

Because of the skillful public relations disinformation campaigns advanced by the fossil fuel industries.

If the problem of climate change and global warming is the result of the burning of fossil fuels (like coal, oil and gas), then the industries that produce those fuels stand to lose.  In response, their strategies are designed to confuse the public on the soundness of the science as well as to play to growing public cynicism about government.

Those strategies were pioneered by the tobacco companies.  It was way back in 1964 that the U.S. Surgeon General warned Americans about the role smoking played in needless heart disease and cancers.  Yet, for decades, the smoking rate hardly budged and policymakers were stymied in their efforts to advance public health measures.  The tobacco industry playbook is now being used by the coal, oil and gas industries – hire well-connected lobbyists, shower politicians with campaign contributions, bamboozle the public with claims over the validity of the science and the effectiveness of policy changes.

And just like the tobacco wars, the fight over climate change could lead to the unnecessary deaths of millions of people.  Unlike the tobacco fight, though, those most affected are likely to be in nations that have the least to do with carbon dioxide emissions.  Low-lying nations like Bangladesh, Indonesia, the islands of the Pacific, and Vietnam are most likely to face catastrophic floods.  In addition, global warming-induced drought will hurt poor nations like Ethiopia and the Sudan.

And unlike tobacco, carbon dioxide – and other greenhouse gases – will remain in the atmosphere for many years after they are released and will plague future generations who may not use fossil fuels at all.

As inhabitants of this small planet, we need to act.  Policies are needed to curtail the potentially catastrophic environmental and public health impacts of global climate change.  If policymakers are too fearful of tackling the issue, or are in the pocket of the fossil fuel industries, then the nation needs new ones.

That’s all for now.  I’ll be keeping an eye on the Capitol and will talk to you again next week.