When asked if he believes in global warming, Neil deGrasse Tyson, the well-known astrophysicist who grew up in the Bronx, responds with a question: “Do you believe in gravity?”

Global warming or climate change—take your pick—is real. It is not a distant threat or prediction. It is our here and now, and it threatens us all by creating new dangers and worsening existing evils. For example, our dependence on fossil fuels, the main cause of the climate crisis, has taken a heavy toll on residents on residents of the Bronx, where I grew up about the same time as deGrasse Tyson.

Poverty and the combination of diesel trucks, waste treatment and power plants and a highway system that has no regard for the area’s residents all add up to a borough that is home to one of the largest concentration of asthma victims in the nation. Some 40,000 of those asthma victims are 1199ers or our immediate family members. Global warming increases ground-level ozone smog production. That worsens asthma as well as triggers other allergies.

We experienced a more dramatic example of extreme climate in 2012, when we were struck by Hurricane Sandy, the second most expensive hurricane in our nation’s history. Members of 1199SEIU, particularly in New York and New Jersey, were affected as both victims and caregivers. Some members on Staten Island and the Rockaways left damaged homes to care for patients.

Warm water fuels hurricanes, and the temperature of the Atlantic Ocean is about two degrees warmer on average than a century ago. We also are more flood-prone because water levels around New York are nearly a foot higher than they were a century ago.

The situation is worse for some cities, such as Miami Beach in Florida, which lies just 10 feet above sea level. Rising seas have forced some Hawaiians and other Pacific Islanders out of their homes and off their islands. California is in the grip of one of its most severe droughts, and we’ve witnessed an epidemic of wildfires out west.

Last year, 1199SEIU Secretary-Treasurer Maria Castaneda, who was born in the Philippines, led a campaign in our union to aid victims of Typhoon Haiyan after it struck her island nation. She and others referred to the tragedy as an unnatural disaster, citing climate change and underdevelopment as reasons for the extensive loss of lives and property.

Climate change is also implicated in the large number of immigrants who arrive on our shore from the global south. A reduction in crop yields already has led to climate refugees from Central and South America.

Issue of war and peace also are impacted by the climate crisis. This year, the U.N. Intergovernmental Panel on Climate Change, the U.S. Defense Department and President Barack Obama have all warned that climate change is becoming an increasing risk to global security.

The long war in the Darfur region of Sudan was largely driven by climate change and environmental degradation. A drought lasting five-and-a-half years played a major role in the current war in Syria.

The climate crisis leaves no one untouched, but, as usual, working people and the poor suffer the most from its effects. The disproportionate impacts were obvious after Hurricanes Katrina and Sandy.

But this, too, can change. U.N. Secretary-General Ban Ki-moon is hosting a meeting of heads of state, business, finance, civil society and local leaders for a climate summit during the last week of September in New York. Its purpose is to commit the participants to low-carbon economies.

And on Sept. 21, 1199SEIU members will join thousands of marchers in Midtown Manhattan representing over 700 organizations that have endorsed the People’s Climate March to demand economic and environmental justice. The march promises to be the largest environmental action in history.

“We’ll take to the streets to demand the world we know is within our reach: a world with an economy that works for people and the planet; a world safe from the ravages of climate change; a world with good jobs, clean air and water, and healthy communities,” reads the call to the march.

A key demand of the action will be the creation of millions of climate jobs and a resilient public health infrastructure. A key to realizing these goals is the building of a broad, diverse movement with labor and working people at its core.

We owe this to our children, our grandchildren and our Mother Earth. As the Lakota Sioux proverb reminds us, “We do not inherit the earth from our ancestors, we borrow it from our children.”