Negligible future warming from: CO2 – CH4 – N2O

By Ed Hoskins

Contents

• Summary

• Introduction

• Water is the most significant Greenhouse gas

• The radiation physics of atmospheric CO2 by Professor William Happer

• The lowest levels of atmospheric Carbon Dioxide contribute most to its Greenhouse warming effect

• The Alarmist reasoning for a major temperature increase from Man-made CO2

• Carbon Dioxide starvation

• Colder Oceans progressively re-absorb CO2 from the atmosphere

• The temperature contributions of the Methane CH4 and Nitrous Oxide N2O

• Conclusions

  • As far as Climate Alarm is concerned Never forget: Sun Tsu’s first art of war

  • The late Professor Sir David MacKay

• Notes:

  • Professor Richard Lindzen

  • Dr. William Happer a short note on Carbon Dioxide warming

  • A long-term history of the atmospheric composition and global temperature

  • References

Summary

The current concentration of atmospheric CO2 at ~420 ppmv, (parts per million by volume), is very low in comparison with the atmospheric CO2 levels of past eons when plants evolved.

At those times with CO2 at ~5000 ppmv+ there was no runaway Global warming.

The warming effectiveness of added CO2 in the atmosphere diminishes logarithmically with increasing concentration, as acknowledged in IPCC reports: IPCC AR5 WG1 (2014) – IPCC AR6 WG1 Ch5 (2021).

At its current low concentration of CO2 at 420ppmv its Global warming effectiveness of is already ~72%+ saturated.

The potential for increased Global warming from any added atmospheric CO2, whether natural, from it’s out-gasing from marginally warmer Oceans or from Man-made additions, is already close to exhaustion.

From its current concentration atmospheric with CO2 at ~420 ppmv even a doubling to 840 ppmv, (Equilibrium Climate Sensitivity, ECS), would cause little additional warming, amounting a ~1% effect of the ~33°C total Greenhouse effect or ~0.33°C.

Attaining ECS at 840 ppmv will take ~150+ years at current growth rates of natural and Manmade CO2 emissions.

All further added CO2 and any minor temperature increase, with likely milder nights, will be a huge benefit to the biosphere and to agriculture.

All attempts by Mankind to limit or even reabsorb further CO2 emissions or other Greenhouse gasses will have no further major controlling effect on Global temperature.

Any actions to reduce CO2 emissions can only be detrimental to the biosphere and economically damaging for any participant Nation.

In order to improve their state of development developing Nations will continue to increase their CO2 emissions by using their indigenous Fossil fuels.

As only a minority of Western Nations are attempting to avoid a supposed Global Overheating Catastrophe by reducing their emissions of Greenhouse Gasses, their policies can only be self-harming and pointless.

Western developed World CO2 emissions amount to ~1/3 of total Man-made CO2 emissions and overall Man-made CO2 emissions amount to ~3% of the total CO2 output of the whole CO2 cycle.

As sequestration of atmospheric CO2 by oceanic creatures is unstoppable in Glacial times, Man kind’s release of CO2 into the atmosphere may even help to extend the viability of plant life in future millennia and thus the continued existence of all life on Earth.

These facts, if anywhere close to reality, entirely negate any need to pursue Net Zero policies to limit or sequester Man-made CO2 emissions, (Carbon Capture and Storage CCS).

However they do justify a radical reassessment of all alarmist concerns for a massive Man-made Global Warming Catastrophe.

Using an IPCC estimate, that the full warming influence of CO2 in the atmosphere is ~8.2% of the 33°C Greenhouse effect amounting to ~2.7°C, the diagram below shows the scale, proportionality and the global warming potential of all main Greenhouse gasses but emphasising the significance of atmospheric Water Vapour.

Read Ed Hoskins’ complete commentary, published on October 24, 2025 here.

Follow Ed’s Substack here

Ed Hoskins is a member of the CO2 Coalition. Hoskins had an educational grounding in science subjects. He qualified both as a Dentist with distinction at Guys in London in 1962 and as an Architect in Cambridge in 1969 with a double first. In 1969 Ed founded Applied Research of Cambridge Ltd. (ARC). He headed it thereafter as Managing Director and later Chairman.

What’s New!

The CO2 Coalition filed this Comment to the EPA on November 3: William Happer EPA GHGRP Comment Nov. 3, 2025 - CO2 Coalition

In case you missed it, Dr. William Happer and Dr. Richard Lindzen joined Joe Rogan on his podcast The Joe Rogan Experience.