---
title: A major milestone.
date: 2013-05-10T19:37:37Z
modified: 2013-05-10T19:37:37Z
permalink: "https://350.org/major-milestone/"
type: post
status: publish
excerpt: "For the first time, NOAA's Mauna Loa observatory recorded an average daily CO2 concentration above 400 parts per million. Globally, we're not yet at annual averages above 400, but this is indeed an important milestone. We've created 400.350.org to reflect on what this means, and talk about what we're doing to cool the planet.\\nPlease take a moment to read and share."
wpid: 30145
---

[![](https://s3.amazonaws.com/s3.350.org/images/400_ppm_attempt_2-01.jpg)

](https://400.350.org)

For the first time, NOAA’s Mauna Loa observatory recorded an average daily CO2 concentration above 400 parts per million. Globally, we’re not yet at annual averages above 400, but this is indeed an important milestone. We’ve created [400.350.org](https://400.350.org) to reflect on what this means, and talk about what we’re doing to cool the planet.

Please take a moment to [read](https://400.350.org) and share.