Praveen Gupta interviews Dr. Hailong Wang, a scientist at the forefront of some fundamental aspects of climate change.

About Dr. Hailong Wang

Dr. Hailong Wang is an Earth Scientist and Team Leader at Pacific Northwest National Laboratory (PNNL). Wang has wide-ranging research expertise in atmospheric aerosols, cloud physics and dynamics, aerosol-cloud-precipitation-climate interactions, light-absorbing impurities in snowpack and sea ice, radiative feedback, and high-latitude climate change and its associated impacts. His research has generated important scientific discoveries and advanced fundamental understanding of the role of aerosols in various critical components of Earth’s climate system. 

Wang serves as an editor for the Atmospheric Chemistry and Physics journal, is a member of the US CLIVAR Process Study and Model Improvement Panel (PSMIP), and is a co-lead of the IARPC Arctic Systems Interactions Priority Area collaboration team.   

Praveen Gupta: Does arctic warming contribute to extreme wildfires in the western US?

Hailong Wang: While the relationship between Arctic warming and western US wildfires is not direct, the warming of the Arctic can influence atmospheric circulation patterns and conditions that increase the likelihood and severity of wildfires in the western US. In a recent study (Zou et al., 2021, Nature Communication) we show that increasing large wildfires during autumn over the western U.S. are fueled by more fire-favorable weather associated with declines in Arctic sea ice during preceding months on both interannual and interdecadal time scales.

“Increasing large wildfires during autumn over the western U.S. are fueled by more fire-favorable weather associated with declines in Arctic sea ice during preceding months on both interannual and interdecadal time scales."

Our analysis based on observations and climate model sensitivity experiments demonstrates and explains the Arctic-driven teleconnection through regional circulation changes with the poleward-shifted polar jet stream and enhanced fire-favorable surface weather conditions over the western US. 

PG: What is the impact of intruding atmospheric rivers into the Arctic?

HW: Atmospheric rivers are long, narrow corridors of moist and relatively warm air that transport large amounts of moisture from lower latitudes to higher latitudes. When these atmospheric rivers extend into the Arctic, they can bring about various changes and consequences. Intruding atmospheric rivers can introduce warmer air into the Arctic region. Warmer air brought by atmospheric rivers can accelerate the melting of sea ice by promoting direct melting and reducing ice growth during the winter months. Atmospheric rivers can bring increased moisture to the Arctic, potentially leading to enhanced precipitation and snowfall. While this might contribute to increased snow accumulation in some regions, it can also lead to more rapid melting if warmer temperatures follow, particularly during the spring and summer.

“Changes in the Arctic can have cascading effects on global climate and weather patterns, highlighting the interconnectedness of the Earth’s climate system."

The changes in temperature, precipitation, and sea ice due to atmospheric rivers can have profound effects on Arctic ecosystems. These changes can impact the distribution and behavior of plant and animal species that rely on specific environmental conditions. Additionally, changes in the Arctic can have cascading effects on global climate and weather patterns, highlighting the interconnectedness of the Earth’s climate system.

PG: How do black carbon (BC) and dust warm the Earth?

HW: Both black carbon (BC) and dust are types of aerosols that have complex effects on the Earth’s climate system, including the potential to contribute to climate warming. BC particles absorb sunlight strongly in the visible and near-infrared wavelengths. When these BC and dust particles are suspended in the atmosphere, they absorb sunlight and convert it into heat. This heats up the surrounding air and, in some cases, even the underlying surface. BC and dust particles can also land on snow and ice surfaces, reducing their reflectivity (albedo). Darker surfaces absorb more sunlight and melt faster, which can contribute to the melting of glaciers, ice sheets, and snow cover.

PG: What are the implications for the Third Pole?

HW: Changes are happening over the third pole; it contains the largest area of glaciers and ice outside the polar regions. This region is highly sensitive to climate change, and its changes have significant implications for both local and global environments. The third pole is also experiencing warming at a rate higher than the global average, causing the retreat of glaciers and reductions in snow cover. This also impacts the availability of freshwater resources through melting runoff and river flows, especially during the dry seasons. The warming also increases the speed of permafrost to thaw, leading to changes in soil stability and release of greenhouse gases.

“The third pole is also experiencing warming at a rate higher than the global average, causing the retreat of glaciers and reductions in snow cover."

Precipitation patterns including timing and intensity of rainfall and snowfall are also changing, which may cause floods and landslides. Changes in glacier melt and snowmelt also impact regional rivers, agriculture and hydropower generation. These changes eventually have complex effects on the Third Pole region’s environment, societies, and economies as well as global sea level rise and communities worldwide.

PG: Recent events across the globe point towards climate modelling deficiencies?

HW: Climate models are never perfect. They are designed to study climate and climate changes in response to changes in greenhouse gases, solar radiation, land cover, and aerosols, rather than the prediction of weather events, by representing the interactions of various components of the earth’s climate system.

“Constraints in computing resources can still limit the level of detail and complexity that can be included in climate models."

Climate models require immense computational power. Constraints in computing resources can still limit the level of detail and complexity that can be included in models. Given these challenges, climate scientists continuously work to improve models by refining processes, incorporating new knowledge, and comparing model outputs with observations. Uncertainties and biases in models are acknowledged, and ensemble approaches (using multiple models) are often employed to provide a range of possible future climate scenarios.

PG: What needs to be done to prevent irreversible outcomes?

HW: This is beyond a scientific question. Preventing irreversible outcomes or tipping points requires urgent and comprehensive action on multiple fronts. The severity of the situation calls for global cooperation, policy changes, technological advancements, climate research, and societal shifts. Here are some examples of key actions:

• Reducing greenhouse gas emissions.
• Promoting sustainable land use and agriculture (with less emissions).
• Protecting forests (acting as carbon sinks).
• Adopting climate-resilient infrastructure and urban planning that can withstand climate impacts.
• Conserving ecosystems as natural carbon sinks.
• Strengthening international collaboration (such as the Paris Agreement).
• Researching and developing innovative climate solutions.
• Increasing public awareness and understanding of climate change and its impacts.
• Considering carbon pricing mechanisms and regulations that limit emissions.
• Building resilience adaptation measures that help communities cope with climate change impacts.

“The window of opportunity to take meaningful action is narrowing, emphasizing the importance of immediate and sustained efforts."

Preventing irreversible climate change requires a collective effort at all levels – from individual actions to international cooperation. Governments, businesses, communities, and individuals all have roles to play in shaping a sustainable and resilient future. The window of opportunity to take meaningful action is narrowing, emphasizing the importance of immediate and sustained efforts.

PG: Many thanks for your brilliant insights into some very intricate challenges. My best wishes for your ongoing efforts towards preserving our planet’s well-being.