Carbon dioxide concentrations in the atmosphere topped 400 parts per million in the Northern Hemisphere for the entire month of April, according to the World Meteorological Organization.
It is the first time in modern times that such a level was reached for an entire month in an entire hemisphere.
Scientists say carbon dioxide levels are a leading cause of climate change, and the 400 ppm threshold is a highly symbolic number.
Carbon dioxide concentrations are believed to have been around 240 ppm at the dawn of the industrial revolution 200 years ago, according to the Intergovernmental Panel on Climate Change. The IPCC said in April that levels would have to stay below 450 ppm in order to avoid the most catastrophic impacts of climate change.
The 400 ppm-level was first reached two years ago in the Arctic, where it is now the norm. Outside the poles, the level was first reached, albeit briefly, a little over a year ago, at the Mauna Loa Observatory in Hawaii.
The WMO now says it expects average levels worldwide to rise above 400 ppm some time in the next two years and stay there.
Michel Jarraud, secretary general of the WMO, which is an agency of the United Nations, said the new benchmark should “serve as yet another wakeup call.”
United Nations climate talks restart June 4 in Bonn, with negotiations scheduled to help set the groundwork for a global agreement to confront climate change next year.
For more information on subscribing to "Energy and Climate Report" or to try it for free, click here.
To sign up for email highlights, click here.
All Bloomberg BNA treatises are available on standing order, which ensures you will always receive the most current edition of the book or supplement of the title you have ordered from Bloomberg BNA’s book division. As soon as a new supplement or edition is published (usually annually) for a title you’ve previously purchased and requested to be placed on standing order, we’ll ship it to you to review for 30 days without any obligation. During this period, you can either (a) honor the invoice and receive a 5% discount (in addition to any other discounts you may qualify for) off the then-current price of the update, plus shipping and handling or (b) return the book(s), in which case, your invoice will be cancelled upon receipt of the book(s). Call us for a prepaid UPS label for your return. It’s as simple and easy as that. Most importantly, standing orders mean you will never have to worry about the timeliness of the information you’re relying on. And, you may discontinue standing orders at any time by contacting us at 1.800.960.1220 or by sending an email to firstname.lastname@example.org.
Put me on standing order at a 5% discount off list price of all future updates, in addition to any other discounts I may quality for. (Returnable within 30 days.)
Notify me when updates are available (No standing order will be created).
This Bloomberg BNA report is available on standing order, which ensures you will all receive the latest edition. This report is updated annually and we will send you the latest edition once it has been published. By signing up for standing order you will never have to worry about the timeliness of the information you need. And, you may discontinue standing orders at any time by contacting us at 1.800.372.1033, option 5, or by sending us an email to email@example.com.
Put me on standing order
Notify me when new releases are available (no standing order will be created)