https://news.yahoo.com/co2-monitors-weapon-paris-climate-fight-114343506.html
Paris (AFP) – Spurred on by growing social movements, cities across the world are getting serious with their climate action, vowing to slash pollution and implement greener laws.
But until now efforts to make some of the largest urban areas on the planet compliant with the Paris climate goals have been hampered by an inability to measure their effect.
The benchmark of a city’s “carbon footprint” currently tracks estimated emissions of greenhouse gases based on voluntary disclosures from industry, traffic authorities, energy firms, among others.
Cities produce around 70 percent of all manmade greenhouse gases, yet estimates of each urban area’s carbon footprint contain a huge margin for error — as much as 30 percent in some cases.
“It requires lots of information to be assessed and generally that creates a lag of 2-3 years,” said Thomas Lauvaux, a researcher at the Environment and Climate Sciences Laboratory (LSCE), told AFP.
Take for example Paris, home of the landmark 2015 agreement that saw nations commit to limiting global temperature rises to “well below” two degrees Celsius (3.6 Farenheit).
The latest official figures were published in 2016 but actually date from 2014: 25.6 million tonnes of CO2 equivalent that year.
While that’s down 9.2 percent compared with 2004, it is hardly the most accurate way of comparing carbon cuts.
