Editor's Note: (Captain Mark Kelly (US Navy, retired) is a combat veteran and former NASA astronaut. The opinions expressed in this commentary are his.)
(CNN) In 2001, I flew my first flight into space aboard Space Shuttle Endeavour. Roughly a decade later, I commanded that same space shuttle on its final flight. That trip was my fourth journey -- and at least for now, my final one -- from this planet into space.
To see our planet as this majestic blue ball floating in the blackness of space is breathtaking. It is truly the most amazing thing I've ever seen. When you see it for the first time it appears perfect. Bright and mostly blue, it's a literal island in our solar system. And make no mistake -- right now, we have no place else to go.
Too often, we forget that this remarkable and fragile place is our only home, a point that was underscored earlier this month at the largest gathering of Earth scientists in New Orleans.
At the conference, the National Oceanic and Atmospheric Administration (NOAA) made a sobering announcement. It came as part of a study of climate change on 2016's weather. The scientists behind the study concluded that without climate change, three of the most severe weather events that took place that year would not have happened. Which events?
1. Heat waves that scorched parts of Asia, including India and Thailand, killing more than 500 people. 2. A patch of unusually warm water in the Pacific Ocean that's had harmful effects on marine life along the coast of North America. 3. And rising air temperatures that made 2016 the hottest in recorded history.
The impact of climate change -- the scars that it's leaving on our planet -- is visible from above, too.
There is visible pollution over large portions of the Earth. You often see this over the Asian sub-continent. The burning of wood and plastic and other materials to heat the homes of hundreds of millions of Indians creates a thick smoke over thousands of square miles.
In China, the problem is more industrialized and more severe. Coal power plants and millions of cars have polluted the skies over eastern China to the extent that I can honestly say I don't believe I have seen the terra firma of eastern China during my four missions into space. It is hidden by a constant blanket of tiny airborne particles of despair.
Perhaps the thing that worries me the most is the massive deforestation underway in areas like Asia and Latin America. Countless trees and millions of square miles of jungle and forest have been removed to accommodate our desires for more -- more wood, more farmland, more pasture, more meat.
When I first looked down upon the Amazon rainforest in 2001, I saw vast areas of jungle and a wide and winding copper colored river that went on and on and on. A river that was impossible to miss and like no other on the planet. By 2011, however, the part that was most noticeable wasn't the river or the jungle but the large swaths of empty land.
From space, it looks empty because we are far away. We don't see the crops or the cattle but we do see the loss. We see the loss of an incredibly diverse ecosystem that once held endless possibilities for new medicines and other discoveries.
We see the loss of a home for so many species that will now have to learn to adapt and survive somewhere else -- or not. And we see the loss of a large amount of carbon, sequestered in a living and breathing ecosystem which created massive amounts of oxygen for all of us.
That carbon, once the giver of life to millions of species all over our planet, now has a new role: greenhouse gas. It will sit in our atmosphere as CO and CO2 for millennia, but in this case as an invisible blanket, warming our planet, changing our climate and creating a cataclysmic mess for future generations.
As an astronaut, I'm often asked about the climate, our environment, and how we are destroying the Earth. My response often surprises people. "Don't worry about the planet, the Earth will be just fine," I tell them. "What you need to worry about is us -- all of us."
This year has been an unequivocal disaster for the future of the planet. President Donald Trump has managed to take a wrecking ball to years' worth of hard work and painstaking negotiations. If not undone, our retreat from the Paris Climate Accords and the EPA's Clean Power Plan alone mean our planet's temperature will rise at a greater rate and our citizen's health will degrade. Other changes in environmental regulations on drilling and auto and appliance efficiency will only make matters worse.
The United States was handed the mantle of leadership on this and so many other issues decades ago for a reason. It is because we are good at it.
Our President has an obligation to look closely at the raw data on climate change. If he does, I think he will reach the same conclusion that I and so many others have reached.
As you pass over the United States in space at night you can see, with your own naked eye, the bright lights that prove we lead the world in energy consumption.
It is very obvious. What's not obvious is whether our country will adequately respond to this reality. As the largest consumer of energy we must lead the way in solving this problem. If we don't do this, who will?