Your house: a crystal bubble melted by climate change

One of our most valued bubbles is our home, a place where we feel safe, protected and surrounded by the persons we love. So what if I tell you that this particularly special bubble is not well prepared for facing climate change? 

 

The architecture, the design, the furniture and the inner arrangement of our houses is a reflection of our culture and traditions, but also of the local climate. Some houses are prepared for really low temperatures, others for tornadoes, fires, earthquakes, and so on. But what happens when our house, is not prepared for some phenomena? For example, the HEAT WAVES.

 

Heat waves are extreme events responsiblefor more deaths than hurricanes, tornadoes, floods and lighting combined. This may be because heat waves take us by surprise in the place where we feel safe. Kovats et al. (2004) discovered that heat waves in London increased the daily mortality by 10% but didn’t increase the hospital admissions, showing that people couldn’t make it to the hospital since heat waves took them unprepared and kill them quickly.

A heat wave is a several-days anomaly in surface temperatures (above 3ºC) relative to the 30-year average temperature for that location. Nevertheless, the definition is fuzzy and varies from one country to another. For example, in the United Kingdom it is considered heat wave when the maximum temperature is above 30ºC for three consecutive days. Here you have an image showing a heat wave over the UK this last summer. 

July 17th, 2016 maximum temperatures. Source: Met Office.

HOW TO BUBBLE-UP A HEAT WAVE? 

So how heat waves are formed? There must be some mechanism producing hot air and another preventing its dissipation. 

The process that produces hot air in this case is just the local warm surface that is heated by radiation. On the other hand, the process that prevents that warm air to escape is called The Omega Block and it’s a high pressure system in the low atmosphere. 

High pressure in the middle layers of the atmosphere acting as a dome. Source: NOAA

Omega blocks are formed when a Jet stream wavy structure amplifies and a high pressure system is trapped within the Jet stream’s crest. Even-though Jet streams are high altitude fast air currents, their impacts on surface weather are huge, almost every storm in mid-latitudes is due to the Jet stream movement.  

Here, you can watch a particularly well-formed Omega Block and its precipitation / temperature consequences (from minute 1:40 to minute 2:50).  You will see how the skies are clean where the high pressure is located, allowing the solar rays to penetrate and holding the warm air near the surface.

SO HOW CLIMATE CHANGE WOULD BE REFLECTED IN HEAT WAVES?

Under climate change scenarios the mid-latitudes Jet streams will move pole-wards (Woolings and Blackburn, 2012) causing that Omega blocks could be formed in northern regions and eventually generating heat waves where they didn’t exist before.

Meehl and Tebaldi (2004) showed this in a heat wave projection under climate change forcing, as you can see below, A and B represent the historical conditions of heat waves in North America and C represents the increment in heat waves under climate change projections. It is easy to note that even-though the historical heat waves were located in the southern part of the map (see A and B), the increment will be in northern areas.

Heat wave severity as the mean annual 3-day worst (warmest) nighttime minima event (4) from NCEP/NCAR reanalyses, 1961 to 1990, for North America (°C) (A) and Europe (B), and from the model for North America (C) and Europe (D). The changes of 3-day worst (warmest) nighttime minima event from the model, future (2080 to 2099) minus present (1961 to 1990) for North America (°C) (E) and Europe (F) are also shown. Source: Meehl and Tebaldi (2004)

Moreover, climate change implies higher rates of warming almost all around the globe, in that sense, during the Omega blocks, higher temperatures will facilitate the heat wave formation and will be more intense as shown in the figure below, where a heat wave index is simulated under different climate changes scenarios. 

Heat Wave Magnitude Index (HWMI). The historical HWMI is shown in blue and red, the historical maximum value is the dashed line. Projections under RCP2.6, RCP4.5 and RCP8.5 are shown in black, blue and green (lines represent median values and circles represent maximum vlues). Russo et al, 2014.

HOW DO WE IMPROVE OUR BUBBLE?

There are plenty of things we can do in order to mitigate and adapt to this changing climate. First of all, consume energy efficiently within our home, use green energies when possible, and save as much as we can. The cleanest energy is the one we don’t use. 

If you have the opportunity to design your house or make some improvements, take into account the climate conditions and your specific location, some windows may work better in the side where sun rises and a well-designed ventilation system needs no energy to work but the wind itself. 

Climate friendly nursery

Finally, you should create the habit of listen to the meteorology office alerts and be aware of what’s going on and how to act under possible conditions that may affect your city like heat waves. 

That’s all for this week, see you next time and remember to share your thoughts below.