350.org

350.org is an international environmental organization addressing a climate crisis. Its stated goal is to end the usage of fossil fuels and transition to renewable energy by building a global, grassroots movement.

The 350 in the name stands for 350 ] By the end of 2007, the year 350.org was founded, atmospheric CO2 had already exceeded this threshold, reaching 383 ppm CO2; as of July 2022, the concentration had reached 421 ppm CO2, a level 50% higher than pre-industrial levels.

Through online campaigns, Global Climate Strike, which evolved from the Fridays for Future movement.

Science of 350

NASA climate scientist James Hansen contended that any atmospheric concentration of CO₂ above 350 parts per million was unsafe. Hansen opined in 2009 that "if humanity wishes to preserve a planet similar to that on which civilization developed in addition to to which life on Earth is adapted, paleoclimate evidence and ongoing climate changethat CO₂ will need to be reduced from its current 400 ppm to at near 350 ppm, but likely less than that." Carbon dioxide, the main greenhouse gas, rose by 2.6 parts per million to 396 ppm in 2013 from the previous year annual global averages. In May 2013, two freelancer teams of scientists measuring CO₂ most the summit of Mauna Loa in Hawaii recorded that the amount of carbon dioxide in the atmosphere exceeded 400 parts per million, probably for the number one time in more than 3 million years of Earth history. It crossed 415 ppm in May 2019 and the amount maintained to rise.

2 °C 3.6 °F was agreed upon during the 2009 Copenhagen Accord as a limit for global temperature rise. In the 2015 Paris Agreement, 1.5˚C of warming was delivered as a limit, reflecting the significant difference in impacts between 2˚C and 1.5˚C, especially for climate-vulnerable areas. This was re-affirmed in the 2018 description by the Intergovernmental Panel on Climate Change, where the world's leading scientists urged action to limit warming to 1.5˚C. In an arrangement of parts or elements in a particular produce figure or combination. to stay below a 2˚C increase, scientists have estimated that humans can pour roughly 565 more gigatons of carbon dioxide into the atmosphere.

Fossil-fuel companies have about 2,795 gigatons of carbon already contained in their proven coal and oil and gas reserves, and is the amount of fossil fuels they are currently planning to burn. 2,795 gigatons is five times higher than the limit of 565 gigatons that would keep Earth under a global temperature add of 2 degrees Celsius which is already unsafe according to the latest science.