Lucy Allis explains the mechanisms behind the Texas snowstorm, where freezing weather fits with global warming, and how we must adapt our infrastructure to prepare for future challenges.
We are constantly being told that the planet is heating up. But if the planet is warming, why has the weather been so cold? Across the world, there has been snow, ice and freezing wind, which doesn’t line up with the idea of ‘warming’. So, what is causing dramatic cold weather, and how is this related to global warming?
The first thing to understand is that climate and weather are not the same thing. Weather changes, including temperature changes, are local, day-to-day fluctuations. Climate is described as ‘the average weather patterns in a region over a long period of time‘. Although we know that climate change is likely to make winters milder and wetter in the UK, this does not mean that cold weather will never happen.
Next, we have to understand the Polar Vortex. The Polar Vortex is a big swirling ring of cold air and low pressure which wraps around both of Earth’s poles. It keeps cold air trapped in the north. When the Polar Vortex gets weaker, it wobbles, which means that it can move south, which can affect Europe, Asia and North America, as it is now. It can also ‘elongate, stretch into different shapes and even split’.
The Polar Vortex has been weakened a lot in the past 30 years due to loss of glaciers and sea ice because of global warming. The Polar Vortex also has a bearing on the Atlantic jet stream – a ribbon of strong winds which can cause changes in wind and pressure which helps to shape the weather. If the Polar Vortex weakens, the jet stream also weakens, and if it strengthens, the jet stream generally strengthens. A stronger jet stream can bring us stormy and wet weather, whereas a weak jet stream can bring very cold air from the Arctic and Europe in the winter.
So, this is what we’ve seen recently in Texas. This extreme cold weather can disrupt travel and hospitals, affect power and water supplies, cause flooding and even cause deaths. In Texas, the winter storm has killed at least 21 people and left millions without power. The situation has exposed big infrastructure problems and has been referred to as ‘a supply-demand disaster on steroids’.
The main reason is infrastructure. When we buy insurance, we work out whether it’s worth it. For example, you might not get your house insured against flooding until there are more floods in your area. This is a risk vs cost decision, which is exactly what happens on larger scales, like for state electricity grids. Put simply, because Texas doesn’t normally have problems with cold weather, there isn’t as much strength in the grid as there is during the summer, when the grid is always put under pressure.
Texas has an independent energy grid, so they cannot get energy support from neighbouring states. Because of this, the decision was made to raise energy prices. This made no difference to people using fixed-rate payments for their power, but has escalated costs for those on variable-rate tariffs which work around weather.
So what can we learn from this, and what do we need to do moving forward? It is crucial that we strengthen our resilience against this type of shock, because they are going to occur more frequently. Part of this includes updating ‘our winter peak resource adequacy assumptions to better reflect weather like this’ and utilising lots of different energy sources. In America, this will require bipartisan collaboration and incentives for meeting energy needs. This relates to overall sustainability too – resilience is key, whether we limit our impacts on the planet or not, because these kinds of events are only going to happen more often.