In 1999, Andrew Ginzel and Kristen Jones unveiled their mixed-media artwork, “Metronome”. The piece is a clock that covers a ten story-high area on the north wall of One Union Square South, a residential building.
The work also included concentric circles of gold-flecked brick. They rippled outward from a round opening, with clouds of steam and music emanating from the wall.
The artists had been thinking about reimagining the piece into something to do with climate change, when they got a letter. Gan Golan and Andrew Boyd wanted to use Metronome to create an art piece. This piece would present the critical window for action to prevent climate change.
This new “Climate Clock” is counting down how much time we have left until the effects of global warming will be irreversible.
The Climate Clock
The Metronome originally counted the hours, minutes, and seconds to and from midnight. It was essentially a creative way to tell the time. For years, however, many onlookers did not understand it. There were several hypotheses, such as that it was tracking the world population, or that it had something to do with PI.
Today, however, there is no mistaking it’s purpose. On Saturday, September 19, a message appeared on the clock that read “The Earth has a Deadline”. Following that, numbers began to appear- 7:103:15:40:07 .
Those numbers represent the years, days, hours, minutes, and seconds we have left until that deadline.
The artists based the numbers on the clock off the Mercator Research Institute on Global Commons and Climate Change. The MCC Carbon Clock shows how much CO2 can be released into the atmosphere to limit global warming to a maximum of 1.5 degrees celsius.
According to the clock, we have just over seven years before reaching the 1.5 degree threshold. We have just over 25 years before reaching a two degree change .
“This is our way to shout that number from the rooftops.” Mr. Golan said just before the countdown began. “The world is literally counting on us.” 
The clock will be on display for the rest of climate week, until September 27. Golan and Boyd say that their goal is to arrange to have the clock displayed permanently somewhere else.
This was not the artists’ first time making a climate clock. They had previously made a handheld version for teenage activist Greta Thunberg. They gave it to her before she spoke at last year’s United Nations Climate Action Summit.
Golan says he got the idea for a much larger, more public display shortly after his daughter was born. That was two years ago. Influences for their clock included the Doomsday Clock, which is maintained by the Bulletin of Atomic Sciences, and the National Debt Clock near Bryant Park in Manhattan.
Bryant says that this number is arguably the most important number in the world.
“And a monument is often how a society shows what’s important, what it elevates, what is at center stage,” he explained .
Golan and Boyd have created a website for the clock to explain its numbers. It also includes a link to a report by the Intergovernmental Panel on climate change. This report estimated that global warming is likely to reach 1.5 degrees Celsius over pre-industrial levels sometime between 2030 and 2052 if it continues at its current rate.
According to the report, that amount of climate change will increase harm to many ecosystems. It will also cause an estimated 54 trillion dollars in damage.
In addition, Golan and Boyd’s website tracks how much of the world’s energy is increasingly coming from renewable resources. It also provides instructions for how to build small, low-cost clocks like the one they gave Thunberg.
“You can’t argue with science,” Mr. Boyd said. “You just have to reckon with it.” 
Stephen Ross is the chairman of Related Companies, the developer that owns the building upon which the climate clock is displayed. He says that the piece will remind the world every day how close we are to catastrophe.
“This initiative will encourage everybody to join us in fighting for the future of our planet.”