How good have climate models been at truly predicting the future?

RealClimate - A new paper from Hausfather and colleagues (incl. me) has just been published with the most comprehensive assessment of climate model projections since the 1970s. Bottom line? Once you correct for small errors in the projected forcings, they did remarkably well. Climate models are a core part of our understanding of our future climate. They also have been frequently attacked by those dismissive of climate change, who argue that since climate models are inevitably … [Read more...]

10 years on

RealClimate - I woke up on Tuesday, 17 Nov 2009 completely unaware of what was about to unfold. I tried to log in to RealClimate, but for some reason my login did not work. Neither did the admin login. I logged in to the back-end via ssh, only to be inexplicably logged out again. I did it again. No dice. I then called the hosting company and told them to take us offline until I could see what was going on. When I did get control back from the hacker (and hacker it was), there was a large … [Read more...]

Sensitive But Unclassified

RealClimate - The US federal government goes to quite a lot of effort to (mostly successfully) keep sensitive but unclassified (SBU) information (like personal data) out of the hands of people who would abuse it. But when it comes to the latest climate models, quite a few are SBU as well. The results from climate models that are being run for CMIP6 have been talked about for a few months as the papers describing them have made it in to the literature, and the first assessments of the … [Read more...]

More than 500 people misunderstand climate change

RealClimate - A consensus is usually established when one explanation is more convincing than alternative accounts, convincing the majority. This is also true in science. However, science-based knowledge is also our best description of our world because it is built on testing hypotheses that are independently reexamined by colleagues. It is also typical that there are a few stubborn people who think they know better than the rest. When it comes to climate science, there is a small group of … [Read more...]

The Antarctic ice sheet is melting and, yeah, it’s probably our fault.

RealClimate - Glaciers in West Antarctica have thinned and accelerated in the last few decades. A new paper provides some of the first evidence that this is due to human activities. by Eric Steig It’s been some time since I wrote anything for RealClimate. In the interim there’s been a lot of important new work in the area of my primary research interest – Antarctica. Much of it is aimed at addressing the central question in Antarctic glaciology: How much ice is going to be lost from the … [Read more...]

Can planting trees save our climate?

RealClimate - In recent weeks, a new study by researchers at ETH Zurich has hit the headlines worldwide (Bastin et al. 2019). It is about trees. The researchers asked themselves the question: how much carbon could we store if we planted trees everywhere in the world where the land is not already used for agriculture or cities? Since the leaves of trees extract carbon in the form of carbon dioxide – CO2 – from the air and then release the oxygen – O2 – again, this is a … [Read more...]

Nenana Ice Classic 2019

RealClimate - Wow. Perhaps unsurprisingly given the exceptional (relative) warmth in Alaska last month and in February, the record for the Nenana Ice Classic was shattered this year. The previous official record was associated with the exceptional conditions in El Niño-affected winter of 1939-1940, when the ice went out on April 20th 1940. Though since 1940 was a leap year, that was actually a little later (relative to the vernal equinox) than the ice out date in 1998 (which wasn’t a leap … [Read more...]

Unforced Variations vs Forced Responses?

RealClimate - Guest commentary by Karsten Haustein, U. Oxford, and Peter Jacobs (George Mason University). One of the perennial issues in climate research is how big a role internal climate variability plays on decadal to longer timescales. A large role would increase the uncertainty on the attribution of recent trends to human causes, while a small role would tighten that attribution. There have been a number of attempts to quantify this over the years, and we have just published a new … [Read more...]

Koonin’s case for yet another review of climate science

RealClimate - We watch long YouTube videos so you don’t have to. In the seemingly endless deliberations on whether there should be a ‘red team’ exercise to review various climate science reports, Scott Waldman reported last week that the original architect of the idea, Steve Koonin, had given a talk on touching on the topic at Purdue University in Indiana last month. Since the talk is online, I thought it might be worth a viewing. [Spoiler alert. It … [Read more...]

Exploring CRUTEM4 with Google Earth

RealClimate - Guest commentary by Tim Osborn and Phil Jones The Climatic Research Unit (CRU) land surface air temperature data set, CRUTEM4, can now be explored using Google Earth. Access is via this portal together with instructions for using it (though it is quite intuitive). We have published a short paper in Earth System Science Data (Osborn and Jones, 2014) to describe this new approach. This is part of ongoing efforts to make our climate data as accessible and transparent as … [Read more...]

Going with the wind

RealClimate - A new paper in Nature Climate Change out this week by England and others joins a number of other recent papers seeking to understand the climate dynamics that have led to the so-called “slowdown” in global warming. As we and others have pointed out previously (e.g. here), the fact that global average temperatures can deviate for a decade or longer from the long term trend comes as no surprise. Moreover, it’s not even clear that the deviation has been as large as is … [Read more...]

Can we make better graphs of global temperature history?

RealClimate - I’m writing this post to see if our audience can help out with a challenge: Can we collectively produce some coherent, properly referenced, open-source, scalable graphics of global temperature history that will be accessible and clear enough that we can effectively out-compete the myriad inaccurate and misleading pictures that continually do the rounds on social media? Bad graphs One of the most common fallacies in climate is the notion that, because the climate was hotter … [Read more...]

The Nenana Ice Classic and climate

RealClimate - I am always interested in non-traditional data sets that can shed some light on climate changes. Ones that I’ve discussed previously are the frequency of closing of the Thames Barrier and the number of vineyards in England. With the exceptional warmth in Alaska last month (which of course was coupled with colder temperatures elsewhere), I was reminded of another one, the Nenana Ice Classic. For those that don’t know what the ‘Classic’ is, it is lottery … [Read more...]

New daily temperature dataset from Berkeley

RealClimate - Guest commentary from Zeke Hausfather and Robert Rohde Daily temperature data is an important tool to help measure changes in extremes like heat waves and cold spells. To date, only raw quality controlled (but not homogenized) daily temperature data has been available through GHCN-Daily and similar sources. Using this data is problematic when looking at long-term trends, as localized biases like station moves, time of observation changes, and instrument changes can introduce … [Read more...]