Wood Romances

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...

Note: I updated this in 2024 to include 2023 data. In a previous post , I covered the distinction between detection and attribution. These are normally considered sequentially. First you detect a signal above natural variability, then you examine if some portion of that signal can be attributed to human activity. The previous post shows that the two are statistically independent from each other, so there is no need to limit attribution studies to signals that are detectable above natural variability. This distinction and clarification I think is important in discussions of tropical cyclone trends. While trends are clear since 1980, the longer term record (since ~1850-1900) is less clear due to selection biases arising from our increasing ability to detect tropical cyclones. This makes detection difficult long term, but that doesn't necessarily mean that scientists can't also examine ways in which human activity is affecting tropical cyclone trends. Detection in the Satellite R...

There is growing evidence supporting the conclusion that AGW is already having an effect on extreme weather events, and those impacts are not beneficial to humanity or to the earth's ecosystems. But the process of arriving at those conclusions is complex, and different types of extreme weather are affected by AGW in different ways. While there is a clear (and obvious) link between AGW and extreme heat, heatwaves, droughts, and flooding, the effects of AGW on other extreme weather are far more difficult to determine. For instance, it may be that AGW is only affecting which parts of the US are more likely to be affected by tornadoes without impacting their frequency. The effect of AGW on Tropical Cyclones (TCs) has been extensively studied, and it appears that there is growing evidence that there are clear connections between AGW and hurricane activity, but I see many reported connections (or lack of connections) misstated by the media, politicians and "think tanks." In ord...