Isn't the “critical point” of Greenland ice sheet – Watt?

Recent published papers The critical point of the complete Greenland ice sheet melting terrain control Petrini et al. is a textbook example of how climate modeling can transform from a scientific tool to a mechanism for creating hysteria. Rather than objectively assessing future possibilities, this article constructs a doomsday scenario on weather forecasts over the next 10,000 years, which will surely scare the public to ensure continued research funding and political influence.

Abstract

The main impact of anthropogenic climate change is the crossing of critical points, which can have serious consequences, such as complete mass loss of the Greenland Ice Sheet (GRIS). Currently, GRIS loses mass at an accelerated rate, mainly due to a sharp decline in its surface mass balance (SMB; balance between snow accumulation and surface ablation from melt and associated runoff). Previous work on the size and nature of the Gris complete melt threshold remains controversial. Here we explore the potential SMB threshold for GRIS complete melting. Effects and interactions of surface melts and glacier isostatic regulation (GIA) in determining this threshold; whether GRIS exhibits characteristics that are usually associated with critical points, such as sensitivity to external forcing. To this end, we forced the Community Ice Cap Model V.2 (CISM2) to compute different SMB climates in multiple elevation classes by cycling in multiple elevation classes with Community Earth System Model v.2 (CESM2) in multi-directional coupled CESM2-CISM2 transients in global climate and GRIS, in transient simulations of altitude CESM2, previously computed different SMB climates in multiple elevation classes. 2 (CESM2)₂ force. SMB calculations in CESM2 have been evaluated by modern observation and high resolution modeling and include advanced representations of the surface melt and snow-snow process.

We found that the complete GRIS melt with a full SMB threshold is 230±84 gt yr^-160% reduction in SMB and 60% reduction in global average warming compared with pre-industry CESM2-CISM2 simulation values. In our simulation, the initial SMB forced changes slightly (from 255 to 230 GT YR^-1) and global average warming above pre-industrial levels (from +3.2 to +3.4 K) can cause sudden changes in the final volume of GRIS (from 50% mass to almost complete dislocation). This nonlinear behavior is caused by SMB-high feedback, which is responsive to surface topographic changes caused by surface melt and GIA. When the effect of melt-induced surface reduction exceeds the reduction of GIA-induced bedrock ridges, while (initially positive) SMB becomes at least thousands of years, the GRIS tips melt from about 50% mass to almost complete melting. We also found that when the ice margins from the central coastal areas had high terrain and SMB, the Gris tip almost completely melted. We show that if we keep SMB fixed (i.e. No SMB – High Feedback) In this relatively narrow area, even if the initial SMB forced exceeds the threshold, it can block the ice sheet retreat and almost completely prevent Gris melt. Based on the minimal GRIS configurations in previous paleoborna modeling studies, we suggest that the ground image of the Midwest may have played a role in ~130-115 kyr bp during the period of preventing the last interglacial cause.

https://tc.copernicus.org/articles/19/63/2025/

Essentially, the study used computer models (in particular the Community Ice Cap Model (CISM2), plus the Community Earth System Model (CESM2)) to simulate the potential melting of the Greenland Ice Cap (GRIS) under “high coco₂” conditions. The authors claim that small changes in surface mass balance (SMB) can trigger “almost complete dehydration” in Greenland, a scenario that is said to be initiated at +3.4°C at a global average warming rate higher than previous industrial levels. They believe that the ice sheet is unstable and vulnerable to so-called “cutting points”, where melt-induced surface reduction and static regulation such as glaciers (GIA) will ensure its near-total collapse.

But here's the problem: this situation is completely driven by the model, with little real-world verification. And, more importantly, it depends on the assumption that expands the scope of scientific credibility.

Let's first solve the elephant in the room: the model. Climate models have long been infamous to predict losses in warmth and ice. The CESM2 model used in this study is based on a set of emission scenarios that usually have little similarity to reality. Many climate fearers rely on representative concentrated pathways 8.5 (RCP 8.5) or their newer equivalents that assume an incredible, almost exponential rise in Co₂ emissions. The authors use the phrase “HighCo₂force” without specifying exactly the emission scenarios they rely on, which is a red flag. If they use the worst emission scenarios (which are common in these papers), then the entire study is essentially a speculative thought experiment rather than a rigorous scientific inquiry.

Furthermore, their models depend on the exact threshold for ice cap collapse, with the SMB shifting from 255 GT/YR to the supposed stimulation of the entire Greenland Ice Plage as a death spiral. This binary “all or nothing” idea is a sign of alarming climate science, in which case, gradually, complex processes have been reduced to dramatic tipping points, which can be conveniently consistent with the key points of political conversation.

The timing of this article is particularly interesting. With skepticism about extreme climate policies, alert scientists and policy makers need fresh headlines to make public anxiety. The message embedded in this study is clear: Take action immediately or face the Ice Sheet Apocalypse.

The funding mechanisms behind this study must also be reviewed. Scientists who predict mild, manageable climate results are rarely amplified by the media or receive substantial grants. But those who think of the worst? They were invited to speak at the global summit, write columns in major newspapers, and develop government policies.

It’s a well-known trick: Use models to create a frightening future situation, cause media buzz, and pressure decision makers to adopt economically disastrous “green” policies while ensuring ongoing flow of research funds.

Although Greenland has experienced ice cubes in recent decades, its ice cap is far below the “critical point”. Research based on real-world observations (not just computer simulations) shows that Greenland’s ice naturally fluctuates naturally with the period when it melts and grows. During the Holocene’s maximum heat (about 8,000 to 5,000 years ago), Greenland’s temperature was significantly higher than today, but the ice sheet was still intact.

Furthermore, the study acknowledges that certain geographical features have historically prevented large-scale ice loss, such as the high terrain in central Greenland. This means that even in extreme warming, the total collapse of the ice sheet is unlikely.

This article is another example of a political agenda hijacking climate science. Instead of a balanced analysis of Greenland’s future, it picks the extremes and sells it as inevitable. Worse, it provides ammunition for policy makers and activists to justify economically serious regulations based on speculative, unverifiable computer models.

Bottom line? The Greenland Ice Sheet is not on the verge of collapse, and no one with fear can change that. But as long as you get funding and media attention from the doomsday forecast, you will expect more.

HT/Chris Martz

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