Broadcast on BBC Radio 4 marks 420 ppm CO2 as a number of the year in 2021

Tim Harford is a numbers guy. It's fitting that he is a host of More or Less: Behind the Stats, the BBC Radio 4 programme and BBC World Service broadcast which explains the numbers that matter to BBC audiences in their everyday lives.

On Boxing Day 2021, Harford bent the ears of his listeners toward a simple, reflective question: What were the most signficant numbers of 2021? Aided by three knowledgeable guests, the result is the 9-minute podcast episode, "Numbers of 2021."

His third guest is Heleen De Coninck, a professor at Eindhoven University of Technology in the Netherlands,and a lead author on several reports by the Intergovernmental Panel on Climate Change. At the six-minute mark, Harford introduces De Coninck as a person who has closely studied the atmospheric CO2 numbers from the Mauna Loa Observatory in Hawaii. With that, she adds the new CO2 record to the short list of significant numbers in 2021:

My number of the year is 420.01. It represents the weekly average of the CO2 concentration in parts per million, and it's the first time—this year—that it actually exceeded 420.

De Coninck is referring to the 2021 record-high in the one-week average level of CO2 in the Earth's atmosphere. How signficant is this? De Coninck tells us in quantitative terms: "Four hundred twenty is an increase of 50% compared to pre-industrial CO2 concentrations." Spoiler alert! She goes further to explain how the economic slowdown of the COVID-19 global pandemic has done little to slow the rise of planet-heating CO2 levels in the atmosphere.

Below, links are provided for listening to the 9-minute broadcast, or the 3-minute discussion at the end with De Coninck. As well, links follow with resources available for tracking and broadcasting information about the global CO2 signal.

CO2 data for broadcasters

Atmospheric CO2 is a leading indicator of global changes ahead, not just in 2021, but every week, month and year for decades to come. Broadcasting additional updates will bring attention and supportive energy to the climate-stabilizing action and investment which has been lagging for decades.

The CO2 records webpage at CO2.Earth gives broadcasters and other people of the world direct access to the most recent, record-high measurement of CO2 levels in the Earth's atmosphere.

CO2.Earth and Show.Earth are continually updating the list of CO2 records as a free, ongoing service for media outlets and concerned citizens who track and distribute information about atmospheric CO2.