Time-lapse videos are a dime a dozen these days, or so it seems. It takes a lot for one to stand out.
That’s why NASA’s video, released earlier this week, of how the Earth has changed over the past 20 years, was so stunning. It makes it look almost as though Earth is breathing. The implication is that our home planet is a living being, both beautiful and fragile.
Naturally, climate-science deniers have taken to message boards — on YouTube and elsewhere — accusing NASA of playing to the climate-change crowd, but anyone with a sense of wonder can’t help but be moved by what they see.
NASA scientists created the time-lapse video from data recorded by satellites orbiting the Earth, and shows how life has changed during a time of great social, economic and geopolitical upheaval. The “breathing” effect is caused by repetition of the seasons, as they change throughout each year.
The colour green represents life on land. Turquoise represents microscopic organisms in the ocean. And white represents winter snows followed by spring thaws. Heat moves around the planet, sea ice grows and shrinks, and vegetation blooms and recedes, changing with the seasons.
That may seem obvious, even to climate-science deniers, but what lends the time-lapse video scientific weight is that it reveals the behaviour of oceans and land simultaneously, over two decades.
“We’ve never had date like this before,” NASA earth scientist Compton Tucker said in a video statement. “Half of all photosynthesis occurs in the oceans, and the other half on land. Having these data to show both at the same time — day after day, month after monthly, year after year, for 20 years — is a great tool to study life on Earth.”
Researchers can both monitor ocean and forest heath, and track conditions in fisheries and agriculture at the same time, to see if there are any connections.
“You can see greening of the Arctic,” NASA oceanographer Jeremy Werdell added, in a video statement from NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “You can see earlier summers, later winters. The view from space has opened our eyes to many different things.”
The project was designed in part to measure the environmental contrasts between El Nino and La Nina, when tropical ocean temperatures in the Pacific shift from being warmer than average to cooler.
Those shifts have far-reaching implications on climate patterns throughout the planet, from severe droughts in California and the Pacific Northwest to more volatile monsoons in South Asia and disruptive rain patterns in food-producing regions as far away as the Horn of Africa.
As with all science, small details play a large role in shaping the big picture. The time-lapse video shows, for example, how phytoplankton growth in the oceans can have a dramatic impact on dry land. The satellites found plankton blooming in ocean regions previously thought to be devoid of life.
The Sea-Viewing Wide Field-of-View Sensor (SeaWiFS), as it’s known officially, was launched in 1997, and spent the next decades and more looking down on us from orbit 700 kilometres (about 435 miles) overhead. The satellite’s original purpose was to collect data on the bio-optical properties of the Earth’s land masses and oceans, but it also watched the Blue Planet’s living colours change with the seasons — hence the time-lapse video released for public view.
Past is prologue. For researchers, long-term trends in the past help provide a glimpse of things to come in the near future. Satellite data is used to monitor the health of agricultural crops, rainforests and ocean fisheries around the world, with a mind to hopefully being able to forecast future disasters.
The difference between now and 1997, when the SeaWiFS satellite was launched, is that technology has advanced to the point where sensors can pick up the finer details at wavelengths that can reveal what’s going on at a chemical level. Changes in the light reflected from plants, for example, can reveal the exact moment when photosynthesis is converting carbon dioxide and water into sugars.
Climate change isn’t just about receding polar ice caps: The NASA survey has also revealed the expansion of so-called “biological deserts,” uninhabitable regions that have grown markedly in the past two decades.
Meanwhile, green shrubs are expanding their reach into areas once believed to be too cold to sustain life.
“The ability to expand your senses into space,” Werdell said, “compress time; watch visualizations like these; see how the ecosystems of land, sea, atmosphere and ice all interact; and then be able to rewind it and watch it again and again — it’s amazing.”