If Global Warming is Real, Why is it SO COLD?? Understanding the Polar Vortex

Let’s cut to the chase: it is COLD in Texas right now.

This week, temperatures in Ft. Worth were in the single digits. It was colder in Dallas than in Anchorage, Alaska. There was snow accumulation in Galveston (aka on the Gulf Coast). The entire state is under a winter storm warning, and many places are seeing the coldest temperatures they have in decades.

For years, scientists have been reporting the hottest years on record. We’ve been told the planet is consistently getting warmer. But how does that make sense when we’re seeing record cold temperatures and snowfall?

Climate vs. Weather

There is an important distinction to make when we have these types of discussions: climate is not the same as weather.

Weather is effectively the atmospheric conditions at a given space and moment in time. This includes characteristics like air temperature, humidity, cloud cover, etc. This extreme cold front would be considered a weather event.

Climate, by contrast, refers to the long-term average weather conditions in an area. It gives a much broader picture and understanding (usually over the span of years, decades, or centuries) than day-to-day fluctuations we see in weather. Examples of climate would be: Texas is usually warm or hot. Florida is hot and humid. Arizona is hot and dry. The Pacific Northwest is cloudy and rainy. Minnesota is cold., etc.

Why this is important: just because it is extremely cold today (weather) doesn’t mean that temperatures aren’t increasing on average (climate).

The Basics of Climate Change

I recognize that there are some differences of opinions as to whether Climate Change is real. I’m not going to go into extensive detail about all of the evidence for Global Warming and Climate Change in this post because it honestly deserves its own blog post. I’ve tried my best to include links and references which do a good job summarizing current data and research. In short: there is an abundance of scientific evidence that Global Warming is happening and that fossil fuel emissions are a major part of it.

Climate Change vs. Global Warming

The term “Climate Change” is an all-encompassing way to refer to multiple aspects of our changing planet, including:

  • Increasing temperatures (e.g. Global Warming)
  • Melting glaciers and ice sheets
  • Rising sea levels
  • More extreme weather events (droughts, hurricanes, wildfires, etc.)
  • Ocean warming & acidification
  • etc.

Often, you’ll see the terms “Climate Change” and “Global Warming” used interchangeably, but there is actually a difference between the two.

Global Warming refers specifically to global temperature increases (which is one aspect of Climate Change). There is a LOT of evidence that temperatures are increasing around the globe, including data from ice cores, tree rings, satellite/remote sensing data, ocean temperature loggers, etc. Although the earth is known to go through periods of warming and cooling, there is a strong consensus among scientists that current trends in global warming are likely a result of human activities, especially the burning of fossil fuels.

Temperature data showing rapid warming in the past few decades, the latest data going up to 2020. According to NASA data, 2016 and 2020 are tied for the warmest year since 1880, continuing a long-term trend of rising global temperatures. The 10 warmest years in the 141-year record have occurred since 2005, with the seven most recent years being the warmest. Credit: NASA’s Goddard Institute for Space Studies. Obtained from NASA.

The Greenhouse Effect

The link between fossil fuels and increasing temperatures is in part a result of something called the Greenhouse Effect. Here’s a simplified version of how the greenhouse effect works:

  • Greenhouse gases (like carbon dioxide and methane) trap heat in our atmosphere
  • Burning fossil fuels like coal, natural gas, and oil has released an unprecedented amount of carbon dioxide into the atmosphere.
  • More greenhouse gas = more heat retention = global temperatures increase

There is a lot of evidence that the earth’s climate (including temperatures) is related to greenhouse gas levels in the atmosphere. There’s also a lot of evidence that atmospheric carbon dioxide levels are the highest they’ve been in the last 800,000 years. (See the figure below. I’ll explain where this data comes from in a different blog post) The scientific consensus is that man-made greenhouse gases like carbon dioxide and methane have contributed significantly to the earth’s increasing temperatures over the last 50 years.

This graph, based on the comparison of atmospheric samples contained in ice cores and more recent direct measurements, provides evidence that atmospheric CO2 has increased since the Industrial Revolution. (Credit: Luthi, D., et al.. 2008; Etheridge, D.M., et al. 2010; Vostok ice core data/J.R. Petit et al.; NOAA Mauna Loa CO2 record.) Find out more about ice cores (external site). Taken from NASA.

How Does Global Warming Impact Weather Patterns?

Long story short: Global Warming and Climate Change are resulting in more frequent extreme weather events including hurricanes, wildfires, floods, droughts, and yes, even cold fronts. But how is that happening?

The Warming Arctic

One phenomenon of Global Warming is that the Arctic is warming faster than the rest of the planet.

Why?

Their are several contributing factors to this, but one has to do with ground cover. Objects which are the color white reflect light (and subsequently, heat), while objects which are the color black absorb light (and heat). Historically, land and oceans in the Arctic were covered in ice, which reflected most heat back into the atmosphere. As the Arctic has warmed, ice which formerly covered most land and oceans has begun to melt, revealing much darker water and land underneath. As a result, the exposed water and ground underneath begin to absorb more heat, causing the Arctic to get warmer, causing more ice to melt faster, and so on. However, climate is a complex and multifaceted issue, so this alone cannot explain the warming temperatures in the arctic, but research suggests that diminishing sea ice has played a major role. There are a lot of other important factors too, but the main takeaway is data shows that temperatures in the Arctic are increasing much faster than the rest of the planet.

Temperature trends for variability in the Arctic and Antarctic regions, taken from Post et al. 2019. The polar regions in a 2*C warmer world. Science Advances 5(12): eaaw9883. The graph on the left shows how surface temperatures have changed faster in the Arctic (green line) compared to the Antarctic (blue line) and the rest of the planet (brown line)

The Polar Vortex

So what does this have to do with weather patterns in the northern hemisphere in places like Texas?

The extreme cold front that we’re dealing with right now is in part the result of something known as the Polar Vortex.

Normally, the Polar Vortex is a large area of low pressure and extremely cold air that is centered in the arctic around the North Pole. It is held in place by the jet stream, a strong air current that surrounds the arctic. Normally, the jet stream is held in place by the temperature difference between warm air to the south and cold air to the north. The greater the temperature difference is, the more stable the jet stream is.

When the temperature differential decreases (either because of cold temperatures at southern latitudes and/or warm temperatures in the arctic), the jet stream weakens, and the super cold air from the polar vortex can essentially wobble southward around the northern hemisphere, bringing extreme cold temperatures. Subsequently, increasing temperatures in the arctic are causing the jet stream to become weaker. This allows more the polar vortex to travel more easily around the northern hemisphere, resulting in more frequent and extreme cold fronts.

Here is a visualization of how it works:

The science behind the Polar Vortex (from NOAA). The depiction on the left shows what the polar vortex is like under normal conditions, when the jet stream is held in place in part due to the temperature differential between the cold arctic and warmer southern latitudes. The image on the right shows what happens when the jet stream weakens. It begins to wave and wobble, allowing ultra cold air normally restricted to the northernmost parts of the globe to move south across the northern hemisphere.

In other words, part of the reason it is so cold outside is because of Global Warming, not despite it. Warming arctic temperatures mean that many places in the northern hemisphere are actually seeing extreme cold fronts more frequently because of reduced stability of the Polar Vortex.

Also, keep in mind that these Polar Vortex events are temperature outliers. Even though they may be associated with record breaking cold temperatures, the average yearly temperatures in most areas are still increasing around the globe.

Regarding Texas’ Power Grid & Renewable Energy

The entire state of Texas has been under winder conditions that our infrastructure is not designed for. This has put unprecedented strain on our power grid, resulting in widespread power outages and rolling blackouts. There are a lot of contributing factors to this, including a reduction in power supply.

Supporters of fossil fuels (such as Gov. Greg Abbott) have been quick to place the blame on renewable energy sources such as wind turbines (some of which have frozen and become non-operational, reducing supply). This might surprise you, but Texas leads the US in wind-powered electricity production. Under normal conditions, roughly 15-20% of Texas’ electricity is produced by wind turbines. Failing wind turbines would have a significant impact on electricity supply in Texas. However, only 7% of ERCOT’s winter capacity is expected to come from wind sources . Most (80%) of the state’s winter energy comes from natural gas, coal, and nuclear power (source).

However, other forms of energy production have also been failing. The simple reality is that all of our power plants are operating under conditions they were not designed for. Other power sources such as gas, coal, and nuclear are also failing. According to ERCOT, Texas has lost 16 gigawatts of renewable energy generation from renewable sources (mainly wind). By contrast, we have lost 30 gigawatts from thermal sources (e.g. gas, coal, and nuclear; source).

So no, renewable energy is not the sole cause of current power shortages.

Final Thoughts

Regardless of why these temperatures are happening, I really hope that everyone is able to stay warm and safe over the next few days.

If you lose power, here are things that you can do to help conserve heat and/or power:

  • Avoid going outside, if you can.
  • Create as much insulation between you and the outside as you can
    • Keep curtains and blinds closed (if you get any direct sunlight, open them to let the sunlight in. Close them again once you are no longer getting direct sun)
    • Roll clothing/towels to block gaps in doors in windows
    • Cover floors (especially tile, linoleum, etc.) with fabric (towels, blankets, or dirty clothing)
  • Close doors to any rooms or closets you are not actively using. Use as few rooms as you can.
  • Keep freezers and refrigerators closed
  • Keep your phone as charged as possible
  • Wear multiple layers of clothing. If your pets are cold, try putting socks on their feet and/or clothing you have that fit them
    • Try to keep clothing dry and avoid wearing cotton, if you can. When cotton gets wet, it loses its ability to insulate, and can potentially increase your risk of getting hypothermia.
  • Make sure that you are eating and drinking. This provides the energy your body needs to produce body heat.

If roads are safe, consider going to an alternate location for heat, either with a friend/family member or at a local warming shelter.

  • Austin: Click here or call 512-305-ICEE (4233) for information about cold weather shelters and warming centers
  • DFW: Click here and here for a list of warming center locations
  • West and Central Texas: Click here for a list of locations in West Texas and the Edwards Plateau. Click here for a list of locations in Central Texas.
  • Houston: Click here for a current list.
  • San Antonio: This is the best list I could find. I will update it if I find a more detailed one.
  • El Paso: Click here for a list or contact 3-1-1 for more information. You can also visit ElPasoReady.org for more information about extreme cold safety.
  • Corpus Christi: Click here for a list of locations.

Know the signs of hypothermia (via the CDC):

  • Shivering
  • Exhaustion or feeling very tired
  • Confusion
  • Fumbling hands
  • Memory loss
  • slurred speech
  • Drowsiness

Hypothermia is a medical emergency. If a person’s body temperature falls below 95 F, seek medical attention immediately. Otherwise, try and warm the person up:

  • Remove any wet clothing
  • Warm the center of the person’s body (chest, neck, head, and groin) using an electric blanket
  • Warm drinks can help increase body temperature (but NOT alcoholic drinks)
  • Click here for more information.

Stay safe, everyone.

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