Rethinking climate change: New paper by Nicola Scafetta

Highlights:
•This paper discusses a number of key open issues in climate science.

•It argues that global climate models still fail on natural variability at all scales.

•Global climate models also likely exaggerate ECS [equilibrium climate sensitivity] and downplay solar influences.

•Empirical alternatives project moderate warming, challenging Net-Zero policies.

•New models that better reflect natural climate drivers and variations are needed.
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Current global climate models (GCMs) support with high confidence the view that rising greenhouse gases and other anthropogenic forcings account for nearly all observed global surface warming—slightly above 1°C—since the pre-industrial period (1850–1900), writes Nicola Scafetta @ Phys.org.

This is the conclusion presented in the IPCC’s Sixth Assessment Report (AR6) published in 2021.

Moreover, the GCM projections for the 21st century, produced under different socioeconomic pathways (SSPs), underpin estimates of future climate impacts and guide net-zero mitigation strategies worldwide.

The prevailing interpretation is that only net-zero climate policies can keep future climate change-related damages within acceptable limits.

Yet such policies carry extremely high economic and societal costs, making it essential to assess whether these certain and immediate costs are fully justified by the current state of climate science.

Full article here.
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Abstract

The Coupled Model Intercomparison Project (CMIP) global climate models (GCMs) assess that nearly 100% of global surface warming observed between 1850–1900 and 2011–2020 should be attributed to anthropogenic drivers like greenhouse gas emissions. These models also generate future climate projections based on shared socioeconomic pathways (SSPs), aiding in risk assessment and the development of costly “Net-Zero” climate mitigation strategies. Yet, as this study discusses, the CMIP GCMs face significant scientific challenges in attributing and modeling climate change, particularly in capturing natural climate variability over multiple timescales throughout the Holocene. Other key concerns include the reliability of global surface temperature records, the accuracy of solar irradiance models, and the robustness of climate sensitivity estimates. Global warming estimates may be overstated due to uncorrected non-climatic biases, and the GCMs may significantly underestimate solar and astronomical influences on climate variations. The equilibrium climate sensitivity (ECS) to radiative forcing could be lower than commonly assumed; empirical findings suggest ECS values lower than 3 °C and possibly even closer to 1.1 ± 0.4 °C. Empirical models incorporating natural variability suggest that the 21st-century global warming may remain moderate, even under SSP scenarios that do not necessitate Net-Zero emission policies. These findings raise important questions regarding the necessity and urgency of implementing aggressive climate mitigation strategies. While GCMs remain essential tools for climate research and policymaking, their scientific limitations underscore the need for more refined modeling approaches to ensure accurate future climate assessments. Addressing uncertainties related to climate change detection, natural variability, solar influences, and climate sensitivity to radiative forcing will enhance predictions and better inform sustainable climate strategies.

On the other hand, a closer examination of observational datasets, paleoclimate evidence, and model performance reveals a more intricate picture—one that merits open discussion among students, researchers, and anyone interested in how climate science is evolving.

My study “Detection, attribution, and modeling of climate change: Key open issues,” published in Gondwana Research, examines several unresolved questions in climate detection, attribution, and modeling.

These issues concern the foundations of how past climate changes are interpreted and how future ones are projected, and they matter because climate projections influence decisions that will shape economies and societies for decades.

A central theme is natural climate variability.

Full paper here.

Source: https://tallbloke.wordpress.com/2026/02/21/rethinking-climate-change-new-paper-by-nicola-scafetta/