Bill Gates about turn on Climate Change

It's a pivot, based on Trump's driving of US policy in a contrarian direction.

If he (Gates) is getting no support (even active suppression of his prior lead idea), then a pivot to the 2nd most important activities is a reasonable alternative.

It's a 'pick your battles' strategy, not an admission of any sort of error.

Cop30 climate summit, which will bring together world leaders in the Brazilian rainforest city of Belém in November, was “a chance to refocus on the metric that should count even more than emissions and temperature change: improving lives”

To improve lives is simple; just reduce the fertility rate to under 2 children per family and there will no housing shortage.   COP30 needs to scrap carbon credits and get into family planning fast.

Carbon dioxide is not a poisonous gas in fact it helps food plants grow??

CliveS said:

Carbon dioxide is not a poisonous gas in fact it helps food plants grow??

Those two statements are true, but irrelevant to the problem.

CliveS said:

Carbon dioxide is not a poisonous gas

However it does drive the green house effect, essentially acting as a thermal blanket at altitude.

More CO2 at altitude means more solar energy absorbed at altitude on it's cascade down to the earth surface. This puts the plants in the wrong climactic growing conditions, so the excess CO2 is no help at all. Solar radiation in-bound has different waveband shape than surface radiation out-bound.

(and beware the CO2 doubling 'zero effect' fallacy used by others (the 400ppm vs 800ppm) - it's like the difference between drowning in 10ft of water vs 20ft of water - zero effect, still dead! 

That is a rather simplistic view of a multi-variable dynamic system in which CO2 is one of the smaller players. Water vapour, as vapour or clouds, has a much greater effect. There are now significant discussions over the reduction in SO2 emissions from shipping affecting aerosols causing an increase in global temperatures:

https://atmosphere.copernicus.eu/aerosols-are-so2-emissions-reductions-contributing-global-warming

This raises the next question of what is the global average temperature and how is the change over time determined/calibrated. Also from Copernicus:

https://climate.copernicus.eu/why-do-we-keep-talking-about-15degc-and-2degc-above-pre-industrial-era

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How do we estimate the global-average temperature?

If we could, we would physically measure the temperature in every corner of the world and calculate an average. But this is of course an impossible task.

The C3S ERA5 dataset is the fifth generation ECMWF reanalysis which combines satellite and in-situ observations into the ECMWF Integrated Forecasting System (IFS) – which is normally used to forecast the weather –  to create a homogeneous picture of the global climate. This allows us to “fill” the gaps in observations, thus creating “maps without gaps”, in a way that is fully consistent with the available observations, also for the most remote places with scarce data available.

Since our ERA5 dataset covers the period from 1940 until a few days before the present, we can estimate the global -average temperature in near-real time and compare it with a reference period, representative of the average current climate for the same period. Following the recommendation of the World Meteorological Organisation, C3S uses the period 1991-2020 as the climatological reference, i.e. the “normal” values used to calculate how “anomalous” the temperature is in a given period.

How do we estimate the global- average temperature during the pre-industrial period?

To compare the ERA5 data with the pre-industrial values, we rely on estimates based on IPCC calculations. The IPCC uses the period 1850-1900 because it’s “the earliest period for which high-quality observations of surface temperatures over the land and ocean are available,” (IPCC). However, these are inevitably characterized by higher levels of uncertainty than the most recent C3S data, as they refer to a period when our observational capacity of the climate was much more limited than it is now. We have used the most recent version of these pre-industrial levels which have been updated following recent IPCC assessments.

Two steps are taken to calculate how the observed temperature of a recent period of time compares with the pre-industrial temperatures. First, we calculate the difference between the temperature of a given month and the average temperature of the reference period (e.g., 1991-2020). Then, following the methodology defined by the WMO IPCC, we add an estimate of the differences between the standard 1991-2020 reference period and the pre-industrial reference period (1850-1900).

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I think that the key words in this is are ‘Estimates’, ‘Gaps’, ‘Uncertainty’.

The increase in Global Average Temperature since preindustrial times is a computer model with lots of factors that can be tweaked to obtain the expected result.

Global temperatures are increasing, that is not in doubt, and is to be expected after the Little Ice Age that is generally accepted to have ended around 1850.

Is the increase enough to be an emergency or just a problem? That takes us back to my OP.

Roger B said:

which CO2 is one of the smaller players.

Here is the major error, especially in a dynamic system, of confusing time scales. CO2 is a slow continuous integration effect, whose effect is discerned over decades. It's also a global level effect as it is dispersed in the upper atmosphere. Everybody gets a bit.

The daily water, weather and rain cycles, do, on their short time scales, feel massive. Even the annual season changes feel large, (especially for those living in mid-continental regions; UK is oceanic!).

The CO2 effects are slowly moving the major climate zones and growing seasons away from the equator toward the polar regions. None of the Shakespearean "Burnam wood do come to Dunsinane" 10 miles stuff, but South of France to the home counties. 

Be wary of the nae sayers.

Roger B said:

There are now significant discussions over the reduction in SO2 emissions from shipping affecting aerosols causing an increase in global temperatures:

All this does is show how factors we historically had chosen to ignore are bigger than we cared to consider. Should we re-sulphurise all the generating plants that caused acid rains through the 'water cycle'?

We'll be putting back lead in the drinking water if we are not careful.  Every time we reduce the lead limits, we discover further measurable effects saying we should have been more aggressive with the limits, resisted by those that said it'll cost too much [for them].

“All this does is show how factors we historically had chosen to ignore are bigger than we cared to consider”

Precisely. Each factor that we find we have missed/ignored in the climate models reduces the validity of the CO2 – Warming relationship that is the ‘Fixed Science’.

Clouds/Cloud cover also seems to be significant:

“Analysis of satellite observations shows that in the past 24 years the Earth's storm cloud zones in the tropics and the middle latitudes have been contracting at a rate of 1.5%–3% per decade. This cloud contraction, along with cloud cover decreases at low latitudes, allows more solar radiation to reach the Earth's surface. When the contribution of all cloud changes is calculated, the storm cloud contraction is found to be the main contributor to the observed increase of the Earth's solar absorption during the 21st century.”

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2025GL114882

(AGU Geophysical Research Letters appears to be a valid publication.)

We should not consider reintroducing know pollutants into our ecosystem. We should however consider what are sensible limits? Is reducing the ‘acceptable’ levels to below background reasonable as has been done in the case of radiation?

“All this does is show how factors we historically had chosen to ignore are bigger than we cared to consider”

Precisely. Each factor that we find we have missed/ignored in the climate models reduces the validity of the CO2 – Warming relationship that is the ‘Fixed Science’.

Clouds/Cloud cover also seems to be significant:

“Analysis of satellite observations shows that in the past 24 years the Earth's storm cloud zones in the tropics and the middle latitudes have been contracting at a rate of 1.5%–3% per decade. This cloud contraction, along with cloud cover decreases at low latitudes, allows more solar radiation to reach the Earth's surface. When the contribution of all cloud changes is calculated, the storm cloud contraction is found to be the main contributor to the observed increase of the Earth's solar absorption during the 21st century.”

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2025GL114882

(AGU Geophysical Research Letters appears to be a valid publication.)

We should not consider reintroducing know pollutants into our ecosystem. We should however consider what are sensible limits? Is reducing the ‘acceptable’ levels to below background reasonable as has been done in the case of radiation?