The video by a National Geographic photographer taken while on an expedition in the Baffin Islands of a polar bear starving to death has been making the rounds on social media these past few days. It is truly heartbreaking and gut-wrenching, and I found I was unable to watch it in its entirety.

The suffering of animals due to us humans is one impact of climate change that I find particularly painful to contemplate. Scientists tell us that our planet is now in the midst of its sixth mass extinction of plants and animals — the sixth wave of extinctions in the past half-billion years. According to the Center for Biological diversity, we’re currently experiencing the worst spate of species die-offs since the loss of the dinosaurs 65 million years ago. As many as 30 to 50 percent of all species could be headed towards extinction by the middle of the century. And this current mass extinction is almost entirely due to human activity.

The video of the polar bear brought to mind a song I wrote sometime back about climate change and its impact on animals, set to the tune of a hit song recorded by The Brothers Four in 1960, called “Green Fields.” If you know the song, you’ll find that the first verse is little changed, while subsequent ones are mostly completely rewritten.

Once there were green fields kissed by the sun
Once there were alleys where rivers used to run
Once there were blue skies with white clouds high above
Once they were part of an everlasting love
These were the green fields where we used to roam

Green fields are gone now, parched by the sun
Gone from the valleys where rivers used to run
Gone are the flocks of birds that swept across the sky
Gone with the fireflies that once lit the summer nights
Where are the green fields that we used to roam?

Whatever happened to this world that is our home?
Where polar bears played in the snows and buffalo did roam?
I look around, and devastation greets my eyes
And it’s all that I can do not to fall to my knees and cry

But I’ll keep on hoping we’ll open up our eyes
I’ll keep on praying one day we’ll realize
We can’t survive unless other creatures thrive
How can we live our lives if the world around us dies?
Where are the green fields that we used to roam?
Oh, where are the green fields that we used to roam?