Keeping to 1.5 degrees would require limiting all future net emissions of carbon dioxide from 2018 onward to 570 gigatons (Gt),3 and reaching net-zero emissions by 2050 (Exhibit 2). How big a hill is this to climb? At the current pace, the world would exceed the 570-Gt target in 2031.
The 1.5C threshold was the stretch target established in the Paris Agreement in 2015, a treaty in which 195 nations pledged to tackle climate change. The agreement aims to limit global warming to "well below" 2C by the end of the century, and "pursue efforts" to keep warming within the safer limit of 1.5C.
The Paris Agreement is a landmark in the multilateral climate change process because, for the first time, a binding agreement brings all nations together to combat climate change and adapt to its effects.
Limiting warming to 1.5°C implies reaching net zero CO2 emissions globally around 2050 and concurrent deep reductions in emissions of non-CO2 forcers, particularly methane (high confidence).
Intensifying wildfires, droughts, floods, hurricanes, storm surges, algal blooms, invasive species, vector-borne diseases, crop failure, economic hardship—suffice to say, we've already gotten a real taste of what 1.5 degrees of warming would feel like.
Today, 195 Parties (194 States plus the European Union) have joined the Paris Agreement. The Agreement includes commitments from all countries to reduce their emissions and work together to adapt to the impacts of climate change, and calls on countries to strengthen their commitments over time.
Melting ice caps and sea level rise The existence of the most low-lying nations potentially depends on the half-degree between 1.5C and 2C, which will add at least 10cm to sea level rise by the end of this century, leaving an extra 10 million people at risk of flooding and storm surges.
By banning new production and use of CFCs, the Montreal Protocol eliminated a significant contributor to climate change, avoiding a potential additional global temperature increase of 0.5 to 1 degree Fahrenheit by 2100.
The Paris Agreement works on a five-year cycle of increasingly ambitious climate action -- or, ratcheting up -- carried out by countries. Since 2020, countries have been submitting their national climate action plans, known as nationally determined contributions (NDCs).
On December 2, 2023, EPA announced a final rule that will sharply reduce emissions of methane and other harmful air pollution from oil and natural gas operations — including, for the first time, from existing sources nationwide.