Last year was another record year for carbon pollution, global temperatures, sea level rise and natural disasters, according to the latest international report on global climate released on Thursday.
More than a dozen CU Boulder researchers contributed to the 34th annual State of the Climate report, led by scientists at the National Oceanic and Atmospheric Administration.
According to the report, concentrations of the Earth’s main greenhouse gases – carbon dioxide, methane and nitrous oxide – reached record highs last year, and the increase from 2022 onwards was one of the highest ever, despite global commitments to reduce emissions.
“We are definitely not on track to curb global warming,” said Xin Lindsay Lan, co-author of the report and a researcher at CU Boulder’s Cooperative Institute for Research in Environmental Sciences (CIRES). “The planet is already warming rapidly, so it is a critical time to reduce greenhouse gas levels in the atmosphere. Instead, we are seeing a rapid increase.”
The report, published in the Bulletin of the American Meteorological Society, also revealed that 2023 was the hottest year on record. Global mean sea levels hit a record high for the 12th consecutive year. Heatwaves, storms and droughts also plagued the planet, while catastrophic wildfires pumped more emissions into the atmosphere.
CU Boulder Today caught up with Lan, who led coverage of global greenhouse gas levels, to discuss the importance of reducing emissions.
Lindsay Lan, Xin
What do you think about the fact that emissions continue to rise?
This is very worrying because global warming is already quite high. Average global warming over the last decade is about 1.1°C above pre-industrial levels. Climate scientists like me are concerned that we could face severe climate crises if global warming exceeds 1.5°C. That is why it is very important that we do our best to limit greenhouse gas emissions and avoid exceeding this threshold.
Many countries and organizations have committed to reducing emissions. Are these efforts working?
Although there have been many efforts to reduce emissions worldwide, our data show that global greenhouse gas concentrations remain at very high levels. Had emissions fallen significantly, the rise in global CO₂ levels would have slowed, but there is no evidence of this. In fact, the increase in CO₂ levels from 2022 to 2023 was the fourth largest in recorded history.
Many countries have committed to achieving net-zero emissions by around 2050. Until then, global CO₂ emissions are likely to continue to rise rapidly.
Why does the climate debate focus so much on CO₂?
CO₂ is the most important greenhouse gas and the main source of global carbon emissions is the use of fossil fuels. It contributes about 66% to the global increase in radiant energy, which directly leads to global warming.
While methane has a greater warming power per molecule than CO₂, it has a shorter lifespan in the atmosphere once released. When CO₂ is emitted, it can stay in the air for thousands of years and continue to trap heat. Much of the CO₂ in the air has been there since the industrial era. Even if we stop emitting CO₂ today, we will continue to experience warming effects from the CO₂ we put into the air.
In 2023, wildfires in Canada emitted 3 billion tonnes of CO₂ – equivalent to the emissions of 647 million cars in one year. Did natural disasters contribute to the record emissions?
The fires certainly contributed to our emissions last year. In addition to the fires and fossil fuel burning, 2023 was an El Niño year, a climate pattern characterized by warmer-than-normal ocean temperatures that release large amounts of heat into the atmosphere.
In warm years like 2023, many forests could come under pressure, reducing their CO₂ uptake. A warmer ocean could also absorb less CO₂ than normal.
What can society do?
What we absolutely need is global cooperation. Greenhouse gases do not stop at national borders because they remain in the atmosphere for a long time. We must work together as a global community to reduce global greenhouse gas emissions.
What can the individual do?
It is important that every individual believes they can make a difference and influence climate change. One of the most important things we can do is limit our energy consumption, because the energy sector is the largest source of greenhouse gas emissions. We can try to use renewable energy for our commute. We can try to use public transport when possible. We can reduce methane emissions by sending less food waste to landfill.
In addition to reducing our own carbon footprint, I would encourage everyone to vote and speak to their MP about their concerns about global warming.
CU Boulder Today regularly publishes Q&A sessions with our faculty members who comment on current issues from the perspective of their scholarly expertise and research/creative work. The answers provided here reflect the expert’s knowledge and interpretations and should not be considered the university’s position on the topic. All publication content may be edited for clarity, brevity, and adherence to university style guidelines.
