Will 2023 be the warmest year on record?
resolved Jan 12

I will resolve this according to NASA's GISTEMP data here (or wherever it's available), counting an exact match (1.02) as a "no". If GISTEMP isn't available, I'll look at NOAA, HadCRUT, or Berkeley Earth temperature data, in that order. See also 2022.

Edit 2023-08-08: past numbers changed to 1.01, so now a 1.02 or higher resolves YES and a 1.01 or lower resolves NO.

Edit 2023-08-15: past numbers changed back to 1.02 again, so now a 1.03 or higher resolves YES and a 1.02 or lower resolves NO. Resolution will be based on what the number is in Jan 2024.

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#NameTotal profit
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2023    87   98  120  100   94  108  119  119  148  134  143  137    117 112     88  105  115  141  2023
Year   Jan  Feb  Mar  Apr  May  Jun  Jul  Aug  Sep  Oct  Nov  Dec    J-D D-N    DJF  MAM  JJA  SON  Year

Per https://data.giss.nasa.gov/gistemp/tabledata_v4/GLB.Ts+dSST.txt
So 1.17 well ahead of 1.01 for 2016 and 2020

@StevenK Resolve please

predicted YES

@uair01 gistemp data not out yet but there is no doubt about it.

predicted YES

@ChristopherRandles No doubt unless they goof up and post the wrong number, in which case resolution might become awkward and I guess I'd try to have uninvolved mods make the decision. But that seems too unlikely to worry about for now.

predicted YES

@StevenK And yes, it won't resolve for another week or so. (edit: this was wrong, they posted the data earlier than I expected)

NASA assembles its temperature record, known as GISTEMP, from surface air temperature data acquired by tens of thousands of meteorological stations, as well as sea surface temperature data from ship- and buoy-based instruments.

The analysis calculates temperature anomalies rather than absolute temperature. A temperature anomaly shows how far the temperature has departed from the 1951 to 1980 base average. Willis and other scientists expect to see the biggest impacts of El Niño in February, March, and April 2024.

(Source - https://climate.nasa.gov/news/3282/nasa-announces-summer-2023-hottest-on-record/)

The WMO says this combination is set to push global temperatures to a new record in the next five years, while climate scientists from a range of other organizations say that this could happen as soon as this year or 2024.

(Source - https://www.weforum.org/agenda/2023/10/climate-2023-hottest-year-on-record/)

@ZahoorSyed So why are you increasing your no position? I would say it is over 99.5% likely.

The more likely than not in next 5 years is for 1.5 above preindustrial when the highest so far is like ~ 1.1 to 1.2C so that is for beating the record by a huge margin.



Oct seems likely to be around 1.2C above 1951-1980 so Nov & December would have to fall to something like just 0.55C above 1951-1980. Not happened since 2007 and while El Nino is having increasing effect, it is just not going to happen without something extraordinary. I am doubting a significant volcanic eruption could have enough effect in time to prevent 2023 being a record hot year.

predicted YES

Polymarket is around 83% based on the same dataset but a slightly stricter threshold, because I'm comparing to the retroactively changed number and they're comparing to what the number was at market creation, so their probability corresponds to >83% here https://polymarket.com/event/will-nasa-record-2023-as-the-hottest-year-on-record

(edit: it seems NASA changed the number back to 1.02, so currently the criteria are the same as the Polymarket market, but this market resolves based on what the number is at resolution time)

@NicoDelon (near-arbitrage, because that market uses a different dataset and maybe a different policy for how to resolve if 2023 is tied for hottest year)

predicted NO

@StevenK Good point.

predicted NO

Changed to NO because of this report: „..end up in the top five hottest years, with roughly a 68 per cent chance of ending up in the top three. Based on their current forecast, there is just over a 20 per cent chance of 2023 becoming the hottest year on record..“

@zedmelody This seems like more important data than how hot it’s felt outside lately. I suspect of a lot of the betting in these markets is shaped by recency and availability biases.

predicted YES

@zedmelody That report also includes

"“The surprisingly strong warming in June 2023, combined with the likelihood of a strong El Niño event, have increased the forecast for the rest of 2023. The statistical approach that we use, looking at conditions in recent months, now believes that 2023 is likely to become the warmest year on record (81% chance),” Rohde explained."

81% without July 2023 temperatures! Also the 20% didn't take account of El Nino, with El Nino this rose to 50%. So my reading of that report is to dismiss 20% and instead look at 50% to 81% and half way in that range is 65.5%. Then we almost certainly have to increase that for July temperatures and we could well arrive at a value in excess of current market 67%.

predicted NO

@ChristopherRandles The contrast is between NOAA and Berkeley more than between two iterations of NOAA’s forecast. But you’re certainly right that July is an important update. 65-67% sound about right to me given the various forecasts. Over 70% doesn’t (at least not yet).

predicted NO

@ChristopherRandles I think "with the likelihood of a strong El Niño event" isn't enough for me, ofc El Niño will happen but like everything in weather, its hard to calculate the impact of this, also El Niño could happen so late it could influence winter (even 2024) .. so its still a NO for me :)


Need over/unders for the annual (and quarterly) numbers from NASA. I'd be yes on over 1.05 for NASA.

predicted YES

@Mirek How is this relevant?

@FlorisvanDoorn Reminds me of the market ups and downs we are seeing here.