BornFromTheVoid

Latest CET projection, based on the 06z GFS. Before corrections, the chances of finishing: Close to average (4.2C to 5.2C) is 39% Above average (>5.2C) is 39% Below average (<4.2C) is 22% The period of the 13th to the 18th is forecast to average 5.0C, equal to the the 91-20 average.

It's based on Equilibrium Climate Sensitivity (ECS) which is temperature response after CO2 has doubled and all the feedbacks have run their course, with a sort of balance again restored (takes 100s to 1000s of years). The transient climate response is the more short term effects.

I've gone with 3.0C to 3.5C. It's simply what the vast majority of evidence suggests (even without climate models). Based on the fact that we've already had 1.1C of warming from less than a 50% increase in CO2, and the planetary energy imbalance (measures of energy coming in vs going out) is continuing to grow, means there's little to support anything under 2C imo.

Some serious cloudscapes out there this evening.

Turning sleety here now, the temp just dipping below 4C. Feeling well below freezing in the wind

This is part of what climate scientists do. It might seem overly complex (as most things are once you start to investigate) but there are ways of narrowing down the values. What do the basic laws of physics tell us? What does the geological record propose? What does the warming so far suggest? Going from the basic laws of physics, there's a 1.2C warming purely from just doubling CO2 before any other feedbacks are considered. This isn't even up for consideration anymore. But then you have the fact that warmer air holds more water vapour, which is another GhG. Warmer air melt snow and ice, reducing the planets reflectivity and allowing even more warming. But then there are uncertainties too. Like, how will clouds react and how will that influence the planets reflectivity? Svante Arrhenius, a noble prize winning physicist, was the first to propose that CO2 was a key player in the ice ages back in the 1800s, and estimated that a doubling would produce 4 to 5C of warming. Over more than a century, with all the scientific advances made, the fact that we're still close to that figure suggest that we're probably near the true answer.

So I thought it might be interesting to see what members think climate sensitivity, or the temperature response to a doubling of CO2, is. The latest IPCC report suggests that equilibrium climate sensitivity is somewhere from 2.0C to 5.0C, but most likely close to 3.0C. (They rule out below 2.0C with high confidence, but only medium confidence about staying under 5.0C). But what do you think, and why?

The temperature has climbed from 7 to 8C here in the last 2 hours, probably thanks to the sunshine. The dew point has dropped from 6.7C to 2.6C in the same time, so the colder polar maritime air is digging in.

Snowed for a while last night a started to stick. I went to sleep shortly after with a little hope but alas, nothing this morning. The Galtees are looking good though. Gonna head up there in about 2 hours.

Mentions light sleet in Gurteen too, which ain't too far. Already down to 1.9C now, dew point 0.6C. Quickly turning to snow and sticking to windows a little.

Temperature beginning to drop here, down 1.1C in the last 45 min to 6.9C. Will need to go much further before sleet even becomes a possibility. EDIT: Plummeting now, down to 5.4C, so a 2.6C drop in little over an hour. Dew point still up at 4.5C, so needs to keep dropping.

Comparing against say the 20th century average, the anomaly for the day is +8.7C. This is certainly the most positive daily anomaly for January and the first above +8C. However, it doesn't come close to the absolute largest daily anomaly. That goes to a rather surprising date, April 29th in 1775. With a mean of 19.7C it's 10.8C above the 20th century average.

The CET minimum for the 1st is 11.2C, provisionally the first January with a min above 11C on record. The max for the 1st is 14.1C, also provisionally the warmest January maximum on record. And unsurprisingly, the mean for the 1st is 12.7C, smashing (provisionally!) the previous record of any January day of 11.6C, and the first January day above 12C.

GFS playing with out hearts again this morning.

Copying and pasting nonsense from climate change denier and alt-right conspiracy theorist blogs ain't a good look. Locking this thread.

A few records for the end of the month. For the mean, both the 30th (11.4C vs 11.0C in 1834) and 31st (12.9C vs 11.1C in 1859) were record breakers. The 31st is also the joint 2nd warmest December day on record, beaten only by 13.1C on December 19th, 2015, and equal to December 12th, 1994. The min was a record on the 31st (11.8C vs 9.6C in 1901) and the 2nd warmest minimum on record for any December day. This also means that the minimum on the 31st was warmer than the previous record mean for the day. The max was a record on the 30th (13.9C vs 13.3C in 2015) and 31st (14.0C vs 12.4C in 1920), and a joint record on the 29th (13.8C also in 1925). (edit due to typo spotted by RJS)

The fog makes for some nice pics. This is on the walk to Bay Lough on the Knockmealdown mountains a few hours ago.

Hi Mucka, thought I'd move this in here and treat it like a question. So, as someone that has a PhD related to Arctic climate change, and curious to see why you think this is fallacious. Also, as a huge Noam Chomsky fan, I have a strong interest in propaganda, and even agree that the BBC spreads a lot of it. Still, I'd like to know why you think this particular piece is propaganda. If we can establish that this is false, and propaganda, then we can start to analyse why this kind of stuff gets pushed.

Latest CET projection, based on the 06z GFS. Before corrections, the chances of finishing: Close to average (4.5C to 5.5C) is 45% (3 days ago was 44%) Above average (>5.5C) is 50% (3 days ago was 43%) Below average (<4.5C) is 5% (3 days ago was 13%) The period of the 9th to the 14th is forecast to average 7.9C, 3.0C above the 91-20 average. Here's the change in projections

It's a commonly used term, just not technically defined. Also, the article comes to the conclusion that it's not related to climate change, so none of it is scaremongering.

Latest CET projection, based on the 06z GFS. Before corrections, the chances of finishing: Close to average (4.5C to 5.5C) is 44% (2 days ago was 42%) Above average (>5.5C) is 43% (2 days ago was 33%) Below average (<4.5C) is 13% (2 days ago was 25%) The period of the 9th to the 14th is forecast to average 8.7C, 3.8C above the 91-20 average. Here's the change in projections

Latest CET projection, based on the 06z GFS. Before corrections, the chances of finishing: Close to average (4.5C to 5.5C) is 42% (3 days ago was 40%) Above average (>5.5C) is 33% (3 days ago was 24%) Below average (<4.5C) is 25% (3 days ago was 36%) The period of the 9th to the 14th is forecast to average 7.3C, 2.4C above the 91-20 average. Here's the change in projections

I'm not sure if it's technically defined anywhere, but in general it means a transition away from previous normal climate/weather patterns to new ones. In the case of these 2 storms, they were unusual in some regards (the extremely rapid deepening of Barra, the direction of Arwen) but not a sign of a climate breakdown.

Winds of 111km/h and a gust of 135km/h on Sherkin Island, just off the south Cork coast Dublin Airport Observations - Met Éireann Observations for Dublin Airport, Ireland - The Irish Meteorological Service WWW.MET.IE Met Éireann, the Irish National Meteorological Service, is the leading provider of weather information and related services for Ireland.