Human activity is rapidly changing weather in North America

We all know the weather can be unpredictable, but if you’ve been out West recently, you might be wondering if things have gone totally haywire. California, in particular, has seen everything from crippling droughts to floods. Could human-caused climate change be behind this roller coaster of weather patterns in Western North America?

A team of researchers led by Professor Jin-Ho Yoon of the Gwangju Institute of Science and Technology believes they’ve uncovered part of the answer.

Teleconnections and North America’s weather

The atmosphere is a vast network of flowing air currents that encircle the globe. These aren’t gentle breezes; they’re powerful patterns influencing our weather.

Scientists have identified key recurring air current patterns within this network, calling them “teleconnection patterns.” These large-scale patterns interact and determine where storms develop and move, influencing the type of weather different regions of the world experience.

For winter weather in the Northern Hemisphere, three specific teleconnection patterns play crucial roles:

• The Pacific North American pattern (PNA)
• The North Atlantic Oscillation (NAO)
• The North American winter dipole (NAWD)

When shifts happen in how these teleconnection patterns interact or fluctuate, we can witness unusual and often extreme weather events.

Studying these variations helps scientists understand the forces driving the increased severity and frequency of things like heavy rains, droughts, or heatwaves in certain parts of the world.

North America’s extreme weather

Professor Yoon’s team used advanced climate models to study how human-caused changes to the atmosphere might be affecting the behavior of these teleconnection patterns. Here’s what they discovered:

NAWD: Force behind North America’s weather

Research reveals that the North American winter dipole (NAWD) has consistently been the most influential teleconnection pattern within the last 70 years. This means it plays a significant role in dictating winter weather patterns across the continent.

PNA vs. NAWD: A shifting rivalry

Scientists observe an evolving dynamic between the Pacific North American pattern (PNA) and the NAWD. These two patterns increasingly operate in contrasting modes: if one exhibits a positive phase, the other often shows a negative phase.

Dr. Yoon highlights that this opposition is likely to drive more extreme weather events – think heavy rainfall or intense dry spells – in areas like California.

The jet stream factor

The key driver behind these teleconnection pattern changes is the jet stream. This powerful, high-altitude air current influences where and how weather systems form. As the jet stream shifts, it creates a ripple effect, altering patterns like the PNA and NAWD.

Human impact: The greenhouse gas connection

The central takeaway is that human activity is the culprit. Greenhouse gas emissions cause the jet stream to shift further north. This northward shift disrupts established weather patterns, directly affecting the behavior of teleconnections like the PNA and NAWD.

Implications from North America’s weather

“Climate models consider a range of factors affecting the atmosphere, including changes in greenhouse gas concentrations resulting from human activities. By running simulations with and without the influence of greenhouse gases, we can compare the results and see how they differ,” explains Dr. Yoon.

The research paints a clear picture: our actions are directly disrupting the intricate network of air currents that govern our planet’s weather systems. This disruption isn’t theoretical; it’s a tangible consequence we’re already experiencing.

The frequency and intensity of extreme weather events – from devastating floods to scorching heatwaves – aren’t simply future possibilities. These events are becoming increasingly common, a consequence of the ongoing changes to the atmosphere caused by greenhouse gas emissions.

Climate change isn’t a distant threat; it’s a present reality with far-reaching consequences. The data from this study underscores the urgency of addressing climate change and implementing solutions that reduce our reliance on fossil fuels and greenhouse gas production.

How to take action

It’s easy to feel overwhelmed when faced with a problem as huge as climate change. But this research makes something clear: to get the weather back to “mostly boring” we need to drastically cut our greenhouse gas emissions. Here’s where you fit into the story:

Spread the Word

Conversations can be a catalyst for change. Discuss this research with friends, family, and your community. Share facts about climate change and the connection to extreme weather to raise awareness and spark discussion.

Assess your impact

Reflect on your lifestyle and identify areas where you can reduce your environmental impact. Consider:

• Energy consumption: Can you switch to energy-efficient appliances, or reduce electricity use?
• Transportation: Are there opportunities to walk, bike, or use public transport instead of driving?
• Waste and consumption: Can you minimize food waste, shop sustainably, or choose products with less packaging?

Demand action

Support businesses that prioritize sustainability and actively work to reduce their carbon footprint. Vote for politicians who advocate for climate policies and hold them accountable for taking action on the climate crisis.

Let’s hope the changing weather serves as a wake-up call to the kind of extremes that could become our new normal if we don’t get serious about climate solutions.

The study is published in the journal Npj Climate and Atmospheric Science.

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