July 21, 2017
Virtually all climate change experts agree that to avoid catastrophe we must first and foremost put everything we can into reducing CO2 emissions. But an increasing number are saying that’s not enough. If we are to limit atmospheric warming to a level below which irreversible changes become inevitable, they argue, we’ll need to actively remove CO2 from the air in fairly hefty quantities as well.
“It’s almost impossible that we would hit 2 °C, and even less so 1.5 [°C], without some sort of negative emissions technology,” says Pete Smith, chair in plant and soil science at the University of Aberdeen and one of the world’s leaders in climate change mitigation.
In fact, scientists from around the world who recently drew up a “road map” to a future that gives us good odds of keeping warming below the 2 ºC threshold lean heavily on reducing carbon emissions by completely phasing out fossil fuels — but also require that we actively remove CO2 from the atmosphere. Their scheme calls for sequestering 0.61 metric gigatons (a gigaton, abbreviated Gt, is a billion metric tons or 0.67 billion tons) of CO2 per year by 2030, 5.51 by 2050, and 17.72 by 2100. Human-generated CO2 emissions were around 40 Gt in 2015, according to the National Oceanic and Atmospheric Administration.
Read More at ENSIA.com