Oddbean

CO2 levels should be a concern though since it's causing global average temperatures to rise too quickly. The boreal forest in north america has evolved to expect significant snowfall over the winter which melts in the spring and feeds rivers, lakes and the soil keeping the forest moist. The last two winters have been absolutely mild with little snowfall. It's actually insane. I grew up in Northern Ontario where snow begins to fall/accumulate in early November and stays until late May. At the peak of winter we have 8ft snow banks. Snow mobile season usually lasts from early December to April. The last two years, its been a few weeks. There was so little in winter 2022 and so little rain in spring 2023 that we had major forest fires throughout northern Ontario and Quebec with smoke affecting daily life all the way to New York City! I know forest fires are normal but those very mild winters (that I have never seen in my life, nor has my father or his father) are causing forests to dry up which impacts so many things. And then warmer air means warmer oceans and that greatly affects ocean currents and marine life... You see where I'm going with this?

The last 2 years have been unusually warm due to water vapor from the January 2022 Tonga eruption, which increased atmospheric water vapor by 10%. Water vapor is the dominant greenhouse gas on Earth and much stronger than CO2. https://en.wikipedia.org/wiki/2022_Hunga_Tonga%E2%80%93Hunga_Ha%CA%BBapai_eruption_and_tsunami https://www.nasa.gov/earth/tonga-eruption-blasted-unprecedented-amount-of-water-into-stratosphere/

The NASA source you shared directly contradicts your claim that the last 2 years have been unusually warm. "In contrast, the Tonga volcano didn’t inject large amounts of aerosols into the stratosphere, and the huge amounts of water vapor from the eruption may have a small, temporary warming effect, since water vapor traps heat. The effect would dissipate when the extra water vapor cycles out of the stratosphere and would not be enough to noticeably exacerbate climate change effects."

It says earlier in the article that the volcano could warm the Earth noticeably Other sources making that same claim: https://eos.org/articles/tonga-eruption-may-temporarily-push-earth-closer-to-1-5c-of-warming https://www.carbonbrief.org/tonga-volcano-eruption-raises-imminent-risk-of-temporary-1-5c-breach/ https://www.nytimes.com/2022/09/22/climate/tonga-volcano-climate.html Here's a published paper saying it raised the atmospheric water vapor by 13%, this will last for years and will warm the surface: https://communities.springernature.com/posts/hunga-tonga-eruption-the-most-remarkable-climatic-event-in-the-last-three-decades

The first article you shared says this: "The model calculated the monthly change in Earth’s energy balance caused by the eruption and showed that water vapor could increase the average global temperature by up to 0.035°C over the next 5 years. That’s a large anomaly for a single event, but it’s not outside the usual level of noise in the climate system, Jenkins said." The second article says this: "The study says that, before the eruption, there was a 50-50 chance that global temperatures would exceed 1.5C above pre-industrial levels at least once by 2026. In its aftermath, the likelihood of exceeding this threshold has increased by seven percentage points – making “imminent 1.5C exceedance” more likely than not." So although it has temporarily warmed the planet further, the major underlying cause is still because of the major excess of GHGs. So sure, maybe once all the water vapour cycles out of the stratosphere, global temperatures will cool slightly, but then again the amount of warming the water vapour may have caused is within the usual level of noise in the climate system. So even if we assume the last two winters are exceptionally mild because of the volcano, more winters like it are likely to come as the planet continues to warm.

Sure but normal warming during interglacial periods happens slow, slow enough for life to adapt. Unlike the current rate of warming which is far exceeding historical warming periods (outside cataclysmic events like volcanism/asteroid impacts). That is the concern.

Absolutely, the current rate of warming is definitely a cause for concern. It's important that we address this issue and work towards finding solutions to mitigate the impacts of climate change. Thank you for bringing attention to this important issue. #ClimateChange #ActNow

Good question, I don't know off the top of my head. Did a quick search and found this. https://www.scientificamerican.com/article/todays-climate-change-proves-much-faster-than-changes-in-past-65-million-years/ About 10 times faster than previous warming periods in the last 65 million years. Would be cool to find papers talking about this and learn more.