NOVA examines new climate technologies that aim to cool the planet

NOVA: Can we cool the planet? broadcast on WITF TV on Wednesday, April 27 at 9 p.m.

  • Christina Zeiders

In NOVA: Can we cool the planet?NOVA is taking a new approach to covering the climate change crisis by exploring new technologies that can help delay the most devastating impacts.

Watch NOVA: Can we cool the planet? Wednesday, April 27 at 9 p.m. on WITF TV, or stream it on demand through the PBS Video app or at

As wildfires rage and extreme weather causes civil unrest, it is clear that emissions reductions alone cannot prevent the disastrous effects of climate change. NOVA joins scientists and engineers tackling climate change with new solutions that could help us cool the planet.

Experts agree that the first step towards cooling the planet is to prevent carbon dioxide (CO2) from entering the atmosphere. At the same time, we can find ways to remove it.

Throughout the special, viewers learn about the different ways scientists and engineers are trying to tackle carbon, including:

  • Jan Würzbacher from Climworks, whose industrial fans suck CO2 from the air.
  • Sandra Snæbjörnsdóttir from CarbFixwhich works to turn the captured CO2 into stone.
  • Aldo Steinfeld from ETH Zürichwhose technology creates liquid carbon from sunlight and air.
  • Apoorv Sinha to Carbon recycling technologieswhich works to recycle atmospheric CO2 to reduce the carbon footprint of concrete.

Even at their full potential, these new technologies could only offset a fraction of global emissions. If we can’t reduce our carbon emissions fast enough, are there technologies that can offer protection against extreme climate risks?

One method scientists are exploring is to change the planet’s reflectivity, making Earth colder, for example, by brightening clouds so they reflect more heat back into space.

Sarah Doherty and Arman Neukermans from Marine Cloud Brightening Project propel salt water particles into the sea clouds, causing the clouds to reflect more heat. David Keith and Frank Keutsch at Harvard go one step further by exploring whether adding reflective particles to the stratosphere could cool the entire planet.

With so much uncertainty surrounding this new technology, some scientists believe it is better to invest in proven machines designed by nature – trees.

NASA research scientist Lola Fatoyinbo-Agueh uses ground and space lasers to measure the amount of carbon stored in forests. A team from the Crowther Lab in ETH Zürich uses artificial intelligence to identify where forests may be expanding and determine how much CO2 could be absorbed.

Whendee Silver is studying how to turn agricultural waste into compost, thereby reducing methane emissions and increasing carbon uptake in the soil.

With no single solution and accelerating climate change, public demand for alternative solutions is growing. Technologies once considered too futuristic or taboo are entering the mainstream; it is essential that we assess each with optimism for the potential they offer…and caution for the risks they carry.

Watch NOVA: Can we cool the planet? Wednesday, April 27 at 9 p.m. on WITF TV, or stream it on demand through the free PBS Video app or at

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