Wood Romances

Cloud Feedbacks are Likely Positive, from Ceppi et al 2026 In my last post I shared what I consider a pretty good "sniff test" for claims that sensitivity is so low that global warming from human fossil fuel emissions can't cause any significant global warming. I showed that low sensitivity claims require the existence of large external forcings that simply can't be found in nature. Today it occurred to me that there's another "sniff test" we can use when people claims that the sum of all climate feedbacks are very small or negative. Let's begin quantifying feedbacks - that is, energy that gets looped back into the system to either amplify or dampen a warming signal. Total feedbacks ( λt ) is the sum of all individual feedbacks which have been quantified in various studies. Here is an accounting of the dominant feedbacks in the climate system: Water Vapor (λwv): 1.80 W/m²/°C Lapse Rate (λlr): -0.50 W/m²/°C Surface Albedo (λsa): 0.35 W/m²/°C Clouds ...

GMST is now 1.4°C above the 1850-1900 Mean Whenever people tell you that climate sensitivity (ECS) is so low that it will never become a problem for human societies, there's a rather simple "sniff test" you can perform to test whether their proposal for ECS is plausible when compared to empirical data. To show this, first I'll show how the energy balance equation works for a rough estimate for ECS. Then I'll show how you can rearrange terms to show that low sensitivity claims force their proponents to propose implausibly high natural forcings that no one has been able to identify. To begin, let's start with the fact that at thermal equilibrium absorbed solar radiation (ASR) equals outgoing longwave radiation (OLR). When these two are not equal, the climate warms or cools until an equilibrium is reached. So when ASR > OLR, there is an earth energy imbalance (EEI), and the surface must warm until ASR = OLR again. So we can expand our equation to account for t...

In a previous post (see that post for the cited literature), I calculated ECS from data provided in the Indicators of Global Climate Change for 2025 (IGCC25). I made 4 calculations using ΔT from two different baselines (1850-1900 and 1790-1839) and two different means for current temperature (the last 4 years and the last 12 years). I’d like to share again the calculations using a 1850-1900 baseline so I can illustrate how feedbacks amplify a warming signal. Here are the calculations in table form: Where ΔFt is total forcings since 1850 and ΔFc is the forcing for doubling CO2. Using these values and the Energy Balance Equation and averaging the two results, we come up with an ECS of 3.4°C. Notice here that to calculate ECS we didn’t have to quantify any feedbacks. We do know that there must be positive feedbacks because Planck sensitivity (Sp) is only about 1.2°C, and we’ve already seen that much warming with just over a 50% increase in CO₂. But the Planck Feedback (λp) is important ...

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...

A couple months ago, I saw that the " Indicators of Global Climate Change 2024 " ( IGCC24 ) was published, which is an annual update on the state of global climate and how it is changing in response to human and natural forcings. The data provides the most up to date information on human emissions and associated changes in radiative forcings as well as an evaluation of the change in temperature. A graphical summary of this is below. From IGCC24 I thought it would be helpful to show how updated values for warming, EEI, and radiative forcings would impact calculations for Equilibrium Climate Sensitivity (ECS). Here's their accounting of the various natural and anthropogenic forcings. Note that s olar forcing in the diagram above is only for 2024 only and so disagrees with the accounting in the table below. Change in Radiative Forcing Forcer 1750-2024 CO2 2.33 ± 0.28 W/m² CH4 0.57 ± 0.11 W/m² N2O 0.23 ± 0.03 W/m² Halogenated GHGs 0.41 ± 0.08 W/m² Ozone 0.5 ± 0.25 W/m² Strat...

Accounting for Climate Forcings Puts ECS Near 3 °C From ClimateBrink The so-called "Climate Working Group," hired by the Department of Energy to write what Roger Pielke Jr termed a "red team" response to climate science  (my initial response is here ) is predictably critical of the central scientific estimate for ECS. The first ECS estimate I know of was calculated by Arrhenius, who concluded that 2xCO2 would cause between 4-6°C warming. This value was revised downward by Gilbert Plass in the 1950s to ~3°C, and since the 1970s this has become the standard estimate. The IPCC currently says the likely range is 2.5-4.0°C, largely as a result of Sherwood et al 2020 (S22),[1] which is still to date the most comprehensive assessment of ECS (Sherwood's likely range was 2.6-3.9°C). There is a growing body of scientific literature arguing that recent observational evidence is more consistent with an ECS closer to 4°C, suggesting that the IPCC may be a bit conservative on...