Tag: climate science

The definitive CO2/CH4 comparison post

There is a new push to reduce CH4 emissions as a possible quick ‘win-win’ for climate and air quality. To be clear this is an eminently sensible idea – as it has been for decades (remember the ‘Methane-to-markets’ initiative from the early 2000s?), but it inevitably brings forth a mish-mash of half-remembered, inappropriate or out-of-date […]

Unforced Variations: Sep 2021

This month’s open thread for climate science topics. Not sure about you, but we are still reading the details of the IPCC report.  We are watching the unfolding hurricane season with trepidation, with particular concern related to the impacts of compound events (and not just those associated with climate), and anticipating another low, if not […]

Sea level in the IPCC 6th assessment report (AR6)

My top 3 impressions up-front: The sea level projections for the year 2100 have been adjusted upwards again. The IPCC has introduced a new high-end risk scenario, stating that a global rise “approaching 2 m by 2100 and 5 m by 2150 under a very high greenhouse gas emissions scenario cannot be ruled out due […]

A deep dive into the IPCC’s updated carbon budget numbers

Guest post by Joeri Rogelj (Twitter: @joerirogelj) Since temperature targets became international climate goals, we have been trying to understand and quantify the implications for our global emissions. Carbon budgets play an important role in this translation. Carbon budgets tell us how much CO2 we can emit while keeping warming below specific limits. We can […]

#NotAllModels

The biggest contribution scientists can make to #scicomm related to the newly released IPCC Sixth Assessment report, is to stop talking about the multi-model mean. We’ve discussed the issues in the CMIP6 multi-model ensemble many times over the last couple of years – for instance here and here. There are two slightly contradictory features of […]

A Tale of Two Hockey Sticks

Two decades ago, the so-called “Hockey Stick” curve, published in 1999 by me and my co-authors (Mann, Bradley and Hughes, 1999), was featured in the all-important “Summary for Policy Makers” (SPM) of the 2001 IPCC Third Assessment report. The curve, which depicted temperature variations over the past 1000 years estimated from “proxy data such as […]

AR6 of the best

Half a dozen takeaways from a first read of the new IPCC AR6 report. As climate scientists we tend to look at the IPCC reports a little differently than the general public might. Here are a few things that mark this report out from previous versions that relate to issues we’ve discussed here before: Extreme […]

We are not reaching 1.5ºC earlier than previously thought

Guest commentary by Malte Meinshausen, Zebedee Nicholls, and Piers Forster Of all the troubling headlines emerging from the release of the Intergovernmental Panel on Climate Change (IPCC) WG1 report, one warning will surely dominate headlines in the next days and weeks: Earth is likely to reach the crucial 1.5? warming limit in the early 2030s. […]

The IPCC Sixth Assessment Report

Climate scientists are inordinately excited by the release of a new IPCC report (truth be told, that’s a bit odd – It’s a bit like bringing your end-of-(seven)-year project home and waiting anxiously to see how well it will be received). So, in an uncharacteristically enthusiastic burst of effort, we have a whole suite of […]

Unforced Variations: Aug 2021

This month is IPCC month – the Sixth Assessment Report from Working Group 1 is out on Monday August 9. We’ll have some detailed comments once it’s out, but in the meantime, feel free to speculate widely (always considering that IPCC is restricted to assessing existing literature…). Open thread – please stick to climate science […]