Wood Romances

 For fun I've been collecting hockey sticks. The following are not complete, but I think they're pretty representative. In fact, I even collected the much maligned Loehle 2008 reconstruction, which has been the darling of contrarian "science." There are numerous issues with that reconstruction, which I document here , but I'm including it because doing so doesn't change the fact that all known temperature reconstructions covering anywhere from NH-extratropical temperatures to global mean temperatures have a hockey stick shape if you include the 21st century. I decided to break this up into three graphs, one showing GMST reconstructions, one showing NH and NH-extratropical reconstructions, and one showing NH-summer and/or NH-growing season reconstructions. I'm showing each with their respective instrumental counterparts (global, NH, and NH-summer). For reconstructions with annual resolution, those are shown faded, but I show running 10-year means for all of...

A prepublication version of the Indicators of Global Climate Change 2025 (IGCC25) has recently been released. This report provides an annual update to IPCC's AR6 WG1 report concerning human emissions and global warming. The data provided as excel spreadsheets related to this report was extensive, and this allows me to produce some graphs I haven't been able to do before. These data do a really good job of showing the relative impact of human and anthropogenic forcings since 1750.  Using HadCRUT5 (1850-1900 Baseline) First I decided to show these forcings with GMST anomalies from HadCRUT5 to see how well the quantifications of forcings agree with observations for warming. This means for this section I'm limiting myself to values from 1850 to present. The graph below shows an update to Gillett's analysis used in AR6 that made it possible to conclude that human activity is responsible for virtually all the warming above the 1850-1900 mean. For this graph, I set HadCRUT5 to...

About 15 years ago a paper was published[1] that included a proxy reconstruction of extratropical Northern Hemisphere temperatures for the last 2000 years. The graph included in the paper sometimes gets adapted by contrarians to give the impression that the Medieval Warm Period was warmer than today. Here's one example: The claim is then made that this is evidence or proof that Mann's hockey stick was a fraud, and scientists like Mann were actively trying to erase the Medieval Warm Period. Of course there are a few problems with this conclusion, beginning with the fact that it appears these people haven't even read the abstract of Ljungqvist's paper: Our temperature reconstruction agrees well with the reconstructions by Moberg et al. (2005) and Mann et al. (2008) with regard to the amplitude of the variability as well as the timing of warm and cold periods, except for the period c. ad 300–800, despite significant differences in both data coverage and methodology. Rather...

Back in 2015, Feldman et al published a paper showing observational and empirical validation of the greenhouse effect. They did this in a pretty ingenious way. They set up two RS-80 sensors at two locations and pointed these at the sky to record downwelling longwave radiation (dLWR) at frequencies absorbed and emitted by CO2. They monitored these sites for 10 years and recorded observations under clear-sky conditions, which would isolate dLWR from CO2 in the atmosphere apart from clouds. Their results showed a 0.2 W/m^2 increase in dLWR, and these results confirmed theoretical predictions regarding the greenhouse effect. In their words: The time series both show statistically significant trends of 0.2 W m−2 per decade (with respective uncertainties of ±0.06 W m−2 per decade and ±0.07 W m−2 per decade) and have seasonal ranges of 0.1–0.2 W m−2. This is approximately ten per cent of the trend in downwelling longwave radiation. These results confirm theoretical predictions of the atmosphe...

The graph above shows annual values and 11-year running means for TSI[1] and GMST anomalies[2] from HadCRUT5. It's very clear that 11-year running means for TSI have varied by very little. The brightest years differ from the dimmest years by only about 0.5 W/m^2, and some of the dimmest years have begun after 2010. However, GMST began to warm around 1910, and after a brief pause from 1940-1970, GMST has increased by an an average of 0.2°C/decade. There is not much evidence for correlation in this graph. If I plot both so that they are similar from 1850 to 1910, they part ways a little after 1910 and then diverge in trend after about 1960. Of course, you could argue that I've chosen a scale for TSI to exaggerate the differences, though this could only potentially be true from 1910-1960, but we can get past this objection by plotting annual TSI values on the x-axis and annual GMST anomalies on the y-axis. Here it's clear that annual TSI is a terrible predictor of GMST anomali...

If you look at graphs of global mean surface temperatures that go back to the last interglacial (LIG or the Eemian), you may notice that GMST anomalies were higher then than during the current interglacial (the Holocene), and current warming has not yet eclipsed the warmest periods of the Eemian. It's a fair question to ask, given that CO2 was ~280 ppm both during the Eemian and the Holocene (and over 420 ppm now), why aren't we yet warmer than the Eemian? The answer to this needs to be given in two parts. First, we'll look at why GMST during the Eemian was warmer than during the pre-industrial Holocene, and second, we'll consider why current warming has not yet eclipsed Eemian warmth.  Long-term changes in GMST occur as a result of the  energy imbalance near the top of the atmosphere, and on time scales of tens to hundreds of thousands of years, orbital cycles play a significant role in determining these GMST changes and the glacial cycles of the Quaternary. In fact, t...