The fate of the West Antarctic Ice Sheet (WAIS) hangs precariously in the balance, with scientists warning that the next few years will be crucial in determining its future. A recent study published in Communications Earth & Environment has shed light on the alarming consequences of WAIS collapse, which could trigger a devastating four meters of global sea level rise over hundreds of years.

The researchers from the Potsdam Institute for Climate Impact Research (PIK), NORCE, and Northumbria University in the UK conducted extensive model simulations spanning 800,000 years to understand how the vast Antarctic Ice Sheet has responded to Earth’s climate fluctuations. Their findings revealed two stable states: one with WAIS intact, which is our current state, and another where the ice sheet has collapsed.

The primary driver of this collapse is rising ocean temperatures around Antarctica, which are mostly supplied by the ocean rather than the atmosphere. Once WAIS tips into the collapsed state, it would take several thousands of years for temperatures to drop back to pre-industrial conditions, reversing the damage.

“We have two stable states: one with WAIS intact and another where it has collapsed,” said lead author David Chandler from NORCE. “Once tipping has been triggered, it’s self-sustaining and seems very unlikely to be stopped before contributing to about four meters of sea-level rise. And this would be practically irreversible.”

The consequences of WAIS collapse would be catastrophic, with four meters of sea level rise projected to displace millions of people worldwide and wreak havoc on coastal communities.

However, there is still hope for a better outcome. Immediate actions to reduce emissions could avoid a catastrophic outcome, giving us a narrow window to act before it’s too late.

“It takes tens of thousands of years for an ice sheet to grow, but just decades to destabilise it by burning fossil fuels,” said co-author Julius Garbe from PIK. “Now we only have a narrow window to act.”

The persistent presence of nitrates in the atmosphere has long been a concern for environmental scientists. Despite efforts to reduce emissions over the past few decades, nitrate levels remain stubbornly high. A recent study published in Nature Communications sheds light on this enigma, revealing that chemical processes within the atmosphere are responsible for the persistence of these pollutants.

The research team led by Hokkaido University’s Professor Yoshinori Iizuka examined nitrate deposition history from 1800 to 2020 in an ice core taken from southeastern Greenland. The results showed a gradual increase in nitrates up to the 1970s, followed by a slower decline after the 1990s. This trend mirrors the changes in emissions of nitrate precursors over the same period.

The study’s findings suggest that factors other than emission reductions are driving the persistence of atmospheric nitrates. The researchers used a global chemical transport model to investigate these factors and discovered that atmospheric acidity is the key culprit. As acidity levels rise, more nitrates become trapped in particulate form, enabling them to persist longer and travel farther.

The implications of this study are significant. Accurate measurements of particulate nitrates in ice cores provide valuable data for refining climate modeling predictions. Moreover, the findings suggest that atmospheric nitrates will soon replace sulfates as the primary aerosol in the Arctic, further amplifying warming in the region.

As Professor Iizuka notes, “Ours is the first study to present accurate information for records of particulate nitrates in ice cores.” The persistence of these pollutants highlights the importance of continued research into atmospheric chemistry and climate modeling. By understanding the complex interactions within our atmosphere, we can better predict and prepare for the challenges that lie ahead.

Monitoring Global Warming: A More Accurate Track to Paris Climate Goals

Climate researcher Gottfried Kirchengast and his team at the University of Graz have developed a new method that enables reliable monitoring of global warming. This breakthrough allows for more accurate predictions about the pace of global warming, which is essential for tracking progress towards the Paris climate goals.

The Paris Agreement of 2015 aimed to limit global warming to well below 2°C and preferably to 1.5°C compared to pre-industrial levels. The latest IPCC report expected the 1.5°C threshold to be reached between 2030 and 2035. However, Kirchengast’s research suggests that this estimate may be too optimistic, with temperatures likely exceeding the 1.5°C mark as early as 2028.

The researchers have created a benchmark record for global surface air temperature from 1850 to 2024, which provides an unprecedented level of accuracy. This new data show a six percent higher increase in global surface air temperature compared to conventional monitoring methods. The team’s findings also enable the distinction between human-induced temperature increases and natural climate phenomena like El Niño.

Kirchengast proposes a four-classes assessment scale to evaluate compliance with the Paris climate goals. This scale would provide clarity on whether countries are meeting or missing their targets, allowing policymakers to make informed decisions.

The researcher emphasizes the importance of standardizing this assessment method through organizations like the World Meteorological Organization and the IPCC. He also suggests defining the phrase ‘well below 2°C’ as ‘below 1.7°C,’ providing a clear and measurable target for countries to work towards.

By using Kirchengast’s research, we can create a more accurate track for monitoring global warming and hold ourselves accountable for achieving the Paris climate goals. This will help us make informed decisions about our actions to mitigate climate change and achieve the desired outcomes for our planet.