I sailed 2,500 miles across the central Pacific Ocean this summer, visiting islands we dream of as paradise, only to be hit hard with the realization that we are one of the last generations who will experience the Earth as we now know it.

The Holy Grail of our quest, the remote and tiny Suwarrow atoll, lies in the northern Cook Islands, some 700 miles from the nearest land. The crew of our research sailing vessel Llyr, a 53-foot ketch, had high expectations of finding pristine coral reefs in this uninhabited place, which only sailboats can reach. We arrived, exhausted and elated, at the end of a rough passage. Bashing our way through 20-foot waves for several hours, we finally slid through the narrow unmarked entrance into a placid lagoon.

Llyr, named for a Welsh sea god, had sailed from Panama to the far-flung islands of French Polynesia (where I came aboard) to survey coral reefs for a citizen science project, Reefcheck (reefcheck.org). Coral reefs are perhaps the most beautiful and wondrously complex ecosystems on the planet. Enchanted undersea gardens, they occupy only 1 percent of the Earth’s seafloor, but contain some 9 million species and a quarter of all marine fish species.

In the more populated islands like Tahiti and Moorea, our crew (mainly a family of five headed by social scientists/ecologists turned maple syrup farmers; see www.berkshiresweetgold.com) saw that the coral reefs were largely dead, which we attributed to local nutrient pollution and overfishing, and (on Moorea) to the crown-of-thorns starfish. Suwarrow atoll, we believed, would be different.

To our surprise and dismay, much of the coral in Suwarrow was dying, some obviously bleached, some algae-covered. We shot videos to record the poor coral health, dove with a couple of manta rays and, with heavy hearts, hauled anchor for the passage to Tonga, without even doing a formal Reefcheck survey.

On the six-day passage to Tonga, we had plenty of time to ponder the decline of the Suwarrow reefs, which we assumed is due to human-caused global warming. No other cause is apparent. Warmer seas cause coral to lose the minute algae that provide their food and oxygen, and the coral bleaches and dies. Acidification due to increased CO2 is another possible explanation.

A healthy coral reef in Tonga in the South Pacific. Coral colonies are collections of minute animals that build huge reefs through their skeletons.

Under stars and clouds on a night watch, with a full moon lighting up relentless waves, it’s natural to think on a geologic time scale. The changes we had seen in the reefs of Tahiti, Moorea, Bora Bora and Suwarrow seemed to me a metaphor for the rest of the planet.

We have known for a long time that the Earth is changing as the climate is disrupted by our fossil-fuel emissions. But I had never so viscerally understood that we are seeing the end of an era in the Earth’s history, the end of conditions that have prevailed since the last ice age. This brief shining moment of our lifetime, and a little time thereafter, seems to be the last, best time on Earth for humans and many other species as we slide into a new and different ecological age.

For anyone in love with and in awe of nature, there is grief in this realization. People who revere the Earth (and especially those working to build public support for measures that will reduce greenhouse gases) need ways of dealing with the anguish-producing news of worsening climate impacts and the absence of remedial action.

Llyr’s crew, after leaving Suwarrow, benefited from some resilience-building measures that seemed to help with climate burnout. First, we talked a lot about our grief and loss, as well as the science of climate and reefs. Second, we stayed actively involved in working on the issues by writing blogs and assembling a documentary. Finally, we immersed ourselves (quite literally) in beautiful natural places that inspired and renewed us.

Unlike the reefs at Suwarrow, the reefs at Tonga — further south of the equator, with noticeably cooler water — were spectacular, a magical tonic for our spirits. To float motionless in clear water and watch the dance of reef creatures displaying their brilliant colors in a symphony of forms and patterns is a spiritual experience. The coral colonies themselves, collections of minute animals — tan, pink, blue and purple — that build huge reefs through their own skeletons, are one of the great wonders of life.

But the news is still disheartening. The United Nations’ top climate experts have just recently given us another warning: If we continue as we are, we will pass the tipping point of severe climate change in less than three decades.

Frightening, yes, but the tipping point that I look forward to is political — the point when we have the critical mass to elect a government that will act effectively. It has happened before, on racism. It is happening on same-sex marriage. When enough people understand the ethical issue of climate — that it is immoral to destroy the future — things will change.

Meanwhile, those who care need to keep the faith, to keep talking and working. We will best maintain the resilience to keep fighting and to limit the harm to the Earth if we pay attention to the thing that gave us passion to start with — nature itself, where it is still possible to draw energy and experience joy.

Chuck Dayton is a retired environmental lawyer.