Breaking Down the IPCC Report and What States Can Do

September 16, 2021



NCEL Point of Contact

Ava Gallo
Climate and Energy Program Manager


IPCC Report Overview

The Intergovernmental Panel on Climate Change, or IPCC, is the world authority on climate science. Comprised of leading scientists from all over the world, the body releases a new comprehensive report on the state of climate science approximately every seven years, with interim reports on more specialized topics. The most recent report from August, Climate Change 2021: The Physical Science Basis, builds on the 2013 report.

Many of the report’s findings are not new. However, the evidence and anticipated severity of human-caused climate change is increasingly stronger. The historic heatwaves, wildfires, hurricanes, and flooding that have overwhelmed the US in just the past year are precursors to increasingly worse climatic disruption. The report’s findings are an alarm bell.

Key Takeaways

Limiting warming to 1.5°C is possible, but time is of the essence. 

Since the Industrial Revolution, humans have emitted enough heat-trapping climate pollutants to warm the world by approximately 1.1°C. In order to limit warming to 1.5°C – a goal stipulated by the Paris Agreement – we must cut carbon pollution in half by 2030 and completely cease emissions by 2050. The Earth’s climate is complex, so there is a lag time between when greenhouse gas pollutants are released and when we start experiencing the associated warming. We are currently on a path to overshoot the target, but if we cease emissions immediately and improve marine and terrestrial ecosystem health so they can better sequester carbon, we may be able to return to below 1.5°C later this century. Some projections show a potential to hit 1.5° of warming by 2030, so the time for steep emissions reductions is now.

Without immediate action, we run the risk of activating irreversible tipping points.

The longer we burn fossil fuels and increase emissions, the more likely we are to trigger catastrophic climate tipping points. Climate tipping points are high-impact events where critical earth systems collapse, leading to irreversible cascading effects. Examples of tipping points include Antarctic ice sheet collapse, which would trigger rapid sea level rise, or the Amazon rainforest turning from a carbon sink to a carbon emitter, which would greatly speed up warming. Already, the Atlantic Meridional Overturning Circulation appears to be weakening; if it slows significantly or even stops, weather patterns and water cycles across continents will shift abruptly.

Curbing methane is key to limiting warming.

Methane is more than 80 times more potent than carbon dioxide over a 20-year time horizon, but it is short-lived in the atmosphere. That means that tackling methane emissions can have an immediate impact in slowing warming. Methane is a precursor pollutant to ozone, so stopping methane emissions would also improve air quality. NCEL recently held a webinar on how states could reduce methane pollution. 

States Have the Tools to Decarbonize

The good news is that there are climate policy solutions out there that states are already implementing. Despite the chaos caused by the COVID-19 pandemic, in 2020 and 2021 state legislatures passed increasingly ambitious bills on climate change. For example, Massachusetts, Rhode Island, and Virginia passed net zero emissions targets to decarbonize the state economy by 2050 or earlier. Washington state passed a comprehensive carbon pricing bill to support the implementation of its own net-zero emissions target passed in 2019. Maine became the first state to legislatively divest from fossil fuels. And, in weeks since the IPCC report came out, New York committed to zero-emissions vehicles and Illinois passed a bill to transition to no-carbon energy by 2050.

The threat of global climate change requires comprehensive solutions, and this is an all-hands-on-deck moment. Every state legislator can have a role in climate solutions, whether they serve on the transportation committee or the bonding committee or anything else. A helpful overview of climate policy solutions by sector is available here.