Modelling sea ice and making climate projections

Imagine the Arctic in the years and decades to come. What environmental changes will occur? What new climate extremes will the area face? How will these developments affect people within and beyond the Arctic? Comprehensive earth system models are critical tools for addressing questions like these. As MARIKA M. HOLLAND explains, they can inform thoughtful approaches for mitigating Arctic environmental degradation.

Sea ice creates a bright, floating ocean seascape that waxes and wanes with the seasons. It is a defining part of the visually stunning Arctic landscape—so much so that it’s easy to forget the Arctic is also alive. Many iconic species that are uniquely adapted to this frozen environment make the Arctic their home. People and communities have thrived on these lands for thousands of years.

But the nature of the Arctic is under extreme threat, and the icy land and seascape we know is disappearing. Over the past several decades, in response to greenhouse gas emissions generated by human activity, the Arctic environment has undergone dramatic changes, including rapid warming, declining sea ice, thawing permafrost, and extensive coastal erosion. We are in unprecedented territory. The consequences of these ongoing changes—for ecosystems, for people living in the region, and for socio-economic and geopolitical concerns—are immense.

What if we could peer into the future? What if we had a “crystal ball” that would allow us to understand what changes are still to come—including how much and what aspects of the Arctic might be lost, and how rapidly these losses will occur? What if we could find out what impacts these changes will have for the species (including humans) that rely on the Arctic environment? And, perhaps most critically, how will the choices we make today determine the Arctic’s future?

Harnessing supercomputers

The good news is that we do have such tools: they are known as comprehensive earth system models. Unlike crystal balls, these models are based on fundamental physics—which defines how the Earth system functions—and they can be described in mathematical equations solved on supercomputers.

These models have been improved and refined over decades as researchers have gained knowledge through theory, observations and experimentation. Recent innovations in observing technologies—for example, from ICESat-2, a satellite-based, photon-counting laser that provides information about the surface height of ice—have enabled a more comprehensive and detailed look at our polar regions. This, in turn, has led to new insights into how the system works—insights we can incorporate into improved models.

These earth system models have proven themselves skilful. They can make accurate predictions and reliably simulate how the Earth responds to influences like volcanic eruptions and greenhouse gas emissions. They also reflect the complexity of the Earth system, where understanding one part requires considering the whole. To capture this intricacy, the models include multiple interacting components and teleconnections between distant, remote regions. They simulate an Arctic—its atmosphere, ocean, sea ice and land—that both responds to and influences the global system.

By providing information about how disruptions in one aspect, such as sea ice cover, can have cascading effects throughout the environment, the models allow us to predict the system’s response to future climate drivers. When paired with ecological conservation, infrastructure or economic information, the systems are powerful tools for decision-making and can help us to mitigate the effects of environmental degradation in the Arctic.

Predicting the Arctic’s response

In addition, these modelling systems are allowing us insights into a host of implications for the changing Arctic. For example, they can simulate projected ocean temperatures, ocean acidity and marine ecosystems, providing information about the shifting likelihood of harmful algal blooms in Arctic waters. This information has profound consequences for the safety of subsistence foods that are of great value to coastal Arctic communities.

The models can also project how sea ice conditions will change seasonally and regionally across the Arctic Ocean, affecting not only ice-dependent species, such as polar bears, seals and walrus, but also shipping accessibility and the risks of pollution and oil spills. The models simulate the location and timing of ongoing permafrost degradation, with effects on the safety and stability of infrastructure. Ongoing research on these topics is allowing us to devise more thoughtful, responsive solutions to Arctic environmental change.

Today’s modelling systems are complex, sophisticated tools that provide critically useful information. But they are not without limitations. We need continued scientific advancements to enhance their applicability to emerging threats. We also need deeper integration across fundamental and applied science to fully realize their potential to support thoughtful decision-making.

The degradation of the Arctic environment is ongoing, rapid and complex. It is stressing ecosystems and communities, with profound effects. Future changes will be more extreme and push the environment into unprecedented territory. We need to create and use the best possible tools and knowledge to address the challenges this will bring. There is no time to lose.

Earth system models can simulate an Arctic—its atmosphere, ocean, sea ice and land—that both responds to and influences the global system.

A work in progress

Although the initial results of our collaboration have been promising, there is still much to do to perfect the detection methods. A key challenge is accurately identifying whale species and distinguishing whales from other large marine animals or objects. Enhancing the precision of our algorithms will be crucial to ensure that the data we transmit are reliable enough to inform effective conservation strategies.

As the Arctic continues to warm, the retreat of sea ice is opening new areas to shipping and industrial exploitation, making effective monitoring and mitigation strategies even more critical. Our aim is to create a comprehensive framework for the sustainable management of Arctic marine resources. We are also collaborating closely with policymakers, Indigenous communities and international stakeholders to implement measures that will protect whale populations and habitats. By combining advanced technologies with traditional ecological knowledge, we aim to adopt a holistic approach to marine conservation.