Trigger warning; complexities ahead! The theory of radiative forcing, a cornerstone of modern mainstream climate science, posits that greenhouse gases like CO₂ and methane trap heat and drive planetary warming. Radiative forcing measures how much the energy balance of Earth's atmosphere is being changed by various factors. Think of Earth as constantly receiving energy from the sun (incoming) and radiating energy back to space (outgoing). When these are balanced, Earth's temperature stays stable.
Radiative forcing tells us when this balance is disrupted. It's measured in watts per square metre (W/m²). A positive radiative forcing (like from supposed greenhouse gases) means more energy is being trapped in Earth's system than is escaping, causing warming. A negative radiative forcing (like from certain types of air pollution) means more energy is escaping than being trapped, causing cooling. For example, if scientists say CO₂ has caused a radiative forcing of +2 W/m², it means that every square metre of Earth's surface is receiving an extra 2 watts of energy due to increased CO₂, roughly equivalent to adding a small LED Christmas light bulb per square metre across the entire planet's surface. The larger the positive radiative forcing, the more warming we can expect; assuming that it occurs in the first place.
This post, inspired by Douglas J. Cotton's arguments (link below), challenges that narrative by examining Venus's extreme surface temperatures and Earth's energy dynamics. It argues that radiative forcing defies thermodynamic principles and observational evidence, proposing instead that gravitational gradients, cloud dynamics, and natural variability better explain planetary temperatures. If radiative forcing is flawed, the trillion-dollar Net Zero agenda collapses, with profound implications for climate policy, and its deindustrialisation of the West. So, while this is bit technical, it is important.
Radiative forcing assumes that greenhouse gases trap outgoing radiation, sending it back to warm a planet's surface. This model, however, inverts cause and effect and violates basic thermodynamics. Consider a lake atop a mountain, with a stream flowing downhill. Building a small dam at the stream's base cannot raise the lake's level, yet radiative forcing implies a similar backward logic: that atmospheric gases can return more energy to a planet's surface than it initially lost.
On Venus, with surface temperatures around 735 K (462°C), the greenhouse model struggles to explain how such heat is sustained. The planet receives minimal direct solar radiation at its surface, less than Earth's 161 W/m², due to its thick, reflective cloud cover. Applying the Stefan-Boltzmann Law, this radiation is insufficient to account for Venus's surface heat, which would require over 16,000 W/m². The notion that CO₂ "traps" heat to maintain this temperature ignores the fact that energy lost via convection and radiation cannot all be returned to the surface. Thermodynamics dictates that energy radiated from cooler atmospheric layers cannot heat an already hotter surface, and convected energy must partially escape to space.
Earth faces a similar issue. The surface receives approximately 161 W/m² of solar radiation, enough for a temperature of about 230 K (−43°C), far below the observed 288 K (15°C). Radiative forcing suggests that greenhouse gases bridge this gap by redirecting outgoing radiation back to the surface. However, this ignores non-radiative cooling processes, conduction, convection, and evaporation, which account for significant surface energy loss. These processes cannot be fully offset by atmospheric re-radiation, as CO₂, CH₄, and H₂O cannot retain or redirect more energy than the surface originally emitted.
Venus's atmosphere, dominated by CO₂ (96.5%), is often cited as a greenhouse effect exemplar. Yet its thermal behaviour undermines this claim. The planet's temperature profile is largely driven by its gravitational lapse rate, the decrease in temperature with altitude due to pressure changes. This gradient, caused by gravity compressing atmospheric molecules, explains Venus's surface heat far better than radiative forcing. The slow circulation of Venus's atmosphere, with no simple day-side-down/night-side-up pattern, further complicates the idea that downward winds or trapped radiation sustain surface temperatures. Convection, not CO₂, dominates energy transfer, and no mechanism exists to return all convected and radiated energy to the surface without violating the second law of thermodynamics.
Earth's atmosphere operates similarly. The tropospheric lapse rate, influenced by gravity and modulated by water vapour, drives temperature gradients. Variations in cloud cover, altitude, and latitude, rather than greenhouse gas concentrations, explain fluctuations in surface temperature and radiative balance. For instance, clouds reflect solar radiation more effectively in tropical regions than in polar ones and shifts in global cloud distribution can account for observed warming trends without invoking CO₂.
The Flawed Foundation of Net Zero
The radiative forcing model assumes that small imbalances in top-of-atmosphere radiation drive surface temperature changes. In reality, surface temperature variations, driven by natural factors like cloud dynamics and lapse rate changes, cause these imbalances. This inversion of cause and effect undermines the rationale for Net Zero policies, which aim to curb CO₂ emissions to mitigate warming. If greenhouse gases have negligible impact on planetary temperatures, as Venus's thermodynamics suggest, then the economic and social costs of decarbonisation are unjustified.
Hamburg's recent Zukunftsentscheid referendum, committing the city to carbon neutrality by 2040, exemplifies this misguided agenda. The city's negligible 0.022% contribution to global CO₂ emissions means its efforts will have no measurable climate impact, yet they threaten to dismantle its industrial base. Policies like these, rooted in the radiative forcing fallacy, risk deindustrialising the West, raising energy costs, and eroding economic stability, all for a crisis that does not exist.
Venus's extreme climate does not validate the greenhouse effect; it exposes its flaws. Gravitational gradients, convection, and natural variability offer a more coherent explanation for planetary temperatures than radiative forcing. Climate science must pivot to these mechanisms, abandoning the flawed assumptions driving Net Zero and climate change alarmism, and its deindustrialisation. Policymakers should pause and reevaluate, prioritising economic stability and scientific rigor over ideological commitments. The trillion-dollar climate agenda, built on a shaky foundation, cannot afford to ignore the lessons of Venus and Earth.