The Honest Broker Roger Pielke Jr.

New climate research in science and policy context

Earlier this week the New York Post asked me to help its readers make sense of some surprising new research on ice dynamics at both poles. The new research appears in a new peer-reviewed paper and a preprint that was just posted.

At the South Pole, Wang et al. 2025 find a record accumulation of ice on the Antarctic ice sheet over the period 2021 to 2023, following a steady decrease from 2002 to 2021. The data comes from NASA’s GRACE series of satellites, which have the ability to precisely measure ice mass.

The figure below shows that the recent accumulation is small in the context of the multi-decadal decline, but is still characterized by the paper’s authors as a “significant reversal.” The paper makes no predictions of whether or how long the accumulation might continue.

At the other end of the planet, at the North Pole, a new preprint by England et al. identifies a “surprising, but not unexpected multi-decadal pause in Arctic sea ice loss.”¹ Their data can be seen below.

From the caption to the figure: “(a,b )Observed sea ice area [106 km2] 1979-2024, (c,d) 20 year-trends of September sea ice area [106 km2/decade] with varying end year from 1998 to 2024, in which the red shaded envelope shows the bounds inside which a linear trend is not statistically significant according to a t-test at 95% confidence.” Source: England et al.

Disucssing these new papers and their significance, my op-ed for the NY Post starts as follows:

When it comes to climate change, to invoke one of Al Gore’s favorite sayings, the biggest challenge is not what we don’t know, but what we know for sure but just isn’t so.

Two new studies show that the Earth’s climate is far more complex than often acknowledged, reminding us of the importance of pragmatic energy and climate policies.

One of them, led by researchers at China’s Tongji University, finds that after years of ice sheet decline, Antarctica has seen a “surprising shift”: a record-breaking accumulation of ice.

The paper takes advantage of very precise measurements of Antarctic ice mass from a series of NASA satellites called GRACE (Gravity Recovery and Climate Experiment).

Since the first GRACE satellite was launched in 2002, Antarctica has seen a steady decline in the total mass of its glaciers. Yet the new study found the decline reversed from 2021 to 2023.

Melting Antarctic ice contributes to global sea-level rise, so a reversal of melting will slow that down. Understanding the dynamics of ice mass on Antarctica is thus essential.

The recent Antarctica shift makes only a small dent in the overall ice loss from 2022, but comes as a surprise nonetheless.

A second new paper, a preprint now going through peer review, finds a similar change at the opposite end of the planet.

Antarctic ice has made a turnaround, scientists say, with an increase in ice mass after years of depletion.

Antarctic ice has made a surprising rebound in mass, scientists say

“The loss of Arctic sea ice cover has undergone a pronounced slowdown over the past two decades, across all months of the year,” the paper’s US and UK authors write.

They suggest that the “pause” in Arctic sea ice decline could persist for several more decades.

Together, the two studies remind us that the global climate system remains unpredictable, defying simplistic expectations that change moves only in one direction.

In 2009, then-Sen. John Kerry warned that the Arctic Ocean would be ice-free by 2013: “Scientists tell us we have a 10-year window — if even that — before catastrophic climate change becomes inevitable and irreversible,” he said.

Today, six years after that 10-year window closed, catastrophic climate change has not occurred, even as the planet has indeed continued to warm due primarily to the combustion of fossil fuels.

Partisans in the climate debate should learn from Kerry’s crying wolf.

On one side, catastrophizing climate change based on the most extreme claims leads to skepticism when the promised apocalypse fails to occur on schedule.

On the other side, studies like the two surprising polar-ice papers reveal climate complexities, but don’t prove climate change isn’t real and serious. . .

This last point is important — climate research is not a scoreboard in a Manichean debate, but instead offers certainties, uncertainties, and even areas of total ignorance that establish a nuanced context for developing robust mitigation and adaptation policies.

The rest of my piece discusses this context. Please head over to the NY Post to read the whole thing and then come back to THB and tell me what you think.

One bit of my original draft was cut for space reasons. Here is that part:

Core understandings of climate science have remained remarkably constant over many decades – Humans affect the climate system in many ways, including greenhouse gas emissions, but also through land management, air pollution, and vegetation dynamics. At a planetary scale the net effect of these changes – driven by carbon dioxide emissions from the burning of coal, natural gas, and oil – is a warming of the planetary system. Anticipating regional and local consequences is far more challenging.

Irreducible uncertainties mean that climate variability and change are about risk management. As the late climate scientist Steve Schneider lamented in 2002, “I readily confess a lingering frustration: uncertainties so infuse the issue of climate change that it is still impossible to rule out either mild or catastrophic outcomes, let alone provide confident probabilities for all the claims and counterclaims made about environmental problems.”

Risk management means that as we balance competing objectives in energy policy we should look for opportunities to reduce costs, increase access, ensure security and reduce the human influences on the environment.

The published version ends with may call for policy makers to keep their eyes on the ball:

The surprises revealed by the two new papers about polar ice also remind us that we need to be prepared for unexpected behavior of the climate system, regardless of the underlying causes of change.

History tells us that climate can shift abruptly, with profound consequences for society.

For instance, the 1870s saw a wide range of climate extremes across the planet, by some estimates contributing to the deaths of 4% of global population.

More recently, the climate extremes of the 1970s led to many new US government programs focused on monitoring and researching climate, such as the National Oceanic and Atmospheric Administration.

Such efforts are crucially important because we can’t always anticipate the results of research. If we could, we wouldn’t need data and science.

Perhaps the most important lesson to take from the new polar-ice findings is that ongoing efforts in Washington, DC to gut climate data and research are deeply misguided.

The global climate system has more surprises in store for us — and we ignore them at our peril.

Read the whole thing here.

Next week here at THB and elsewhere, I’ll have much more on NOAA and current efforts to gut climate data and research.

Before letting you go today — last week I sat down with John Hook from Fox 10 in Phoenix and engaged in a deep discission of climate science and energy policy. You can see the full interview below. Thanks to John for the opportunity and the informed questions — I enjoyed the interview and the chance to explore nuances of climate and energy.

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