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.

One last cup before the storm: climate change and coffee

The world consumes more than 300 000 cups of coffee per day, how many of those are yours?

As the second-most traded commodity, the climatic impacts on coffee would have repercussions not only in the global economy, but also in your BUBBLE OF DAILY HABITS AND PLEASURES that you took for granted… until now.

THE BEAN BELT

Every plant species has its own optimum growing conditions in terms of temperature, precipitation and soil nutrients. It just takes a glance to the image bellow to realize that the top 8 coffee producers in the world are located in tropical latitudes, where the climate conditions for the optimum growing are met.

Figure 1. The bean belt. Source: Camano island coffee

In the table below, I summarized some of the adequate climatic parameters for the ideal growing of Coffea arabica (the most common species of coffee) in its different phenological stages.

Table 1. Coffee climatic conditions. Own elaboration, References: Moraes, 1963; IBC, 1985; IARC, 1991; Carvajal, 1984;  Camargo, 1985;  Alegre, 1959; Maestri and Barros, 1977;  Haarer, 1958;  Coste, 1992

Not just the climate conditions are complex by themselves, but also the fact that a coffee plant takes three years to give its first fruit. Therefore, seasonal variability cannot be a factor that shifts from one temperature to another in order to satisfy the different phenological-stages necessities, rather it should be the mean annual values the one that oscillates around those specific temperatures.

When the thresholds are passed, a great variety of problems start to arise. For example, the fruit production of Coffea arabica drops by 10% per degree Celsius above 24°C (Nunes et al., 1968).

LOSS OF HABITAT

Climate variability is an important factor in coffee production due to the its high sensitivity. In the case of El Niño Southern Oscillation, the high temperatures and extreme storms or droughts had affected entire coffee regions in the short-term (Ubilava, 2011). Under the present climate change those amplified events are tending to increase.

The Intergovernmental Panel on Climate Change (IPCC) have compiled meticulous observations of different variables over the globe that offer a complete overview of the climatic trends. For example, the figure below shows the frequency of warm days and warm nights over a 60 years period. It is observed that the intense red areas that represent the highest increment in frequency are located in regions of high coffee production. As stated in Table 1, both night and day temperatures are very important for the plant development.

Figure 2. Frequency of warm days and warm nights. Source: IPCC

Several studies had demonstrated the strong impacts of climate change on agriculture (e.g. Pesket, 2007; Turral et al., 2011; Wiebe et al., 2015). And more specifically, the correlation of atmospheric variables and coffee production fluctuation (Gay et al., 2006; Davis et al., 2012), so a coffee crisis due to habitat loss is imminent.

PLAGUES

Coffee rust is a leaf disease with intensities that had grown recently, some affected coffee producers are: Colombia from 2008 to 2011; Central America and Mexico (2012-2013); and Peru and Ecuador (2013; Avelino et al., 2015). The fungus that causes this epidemics is a parasite that affects the leaves and eventually lead to the death of the branches, causing major crop losses. The coffee rust driving factors are mainly associated with extreme weather such as fully packed cloudy skies and high rainfall, which facilitates the plague spreading (Cristancho et al.,2015).

COFFEE SCENARIOS

The future for the coffee is more bitter than I would like. The current knowledge on coffee species and climate projections allow scientists to explore future scenarios for coffee production. For example, Davis et al.(2012) projected suitable lands for Arabica production in Ethiopia under different climate change scenarios, as observed in the Figure below, the ideal land for coffee plantations (first row) will virtually disappear under every scenario by 2080, and by 2050 will remain a few locations. As the rigor of the climatic threshold decreases, the area of coffee production increases, but it will be lands that have intermediate or marginal suitability that will ultimately impact in the farmers economy and in the coffee quality.

Figure 3. Optimal, Intermediate and marginal suitability for coffee plantations by 2020, 2050 and 2080. Source: Davis et al., 2012.

Once we understand the climatic conditions for the adequate species growth and the future projections under climate change scenarios, it’s not surprising to realize that the world has already a coffee deficit since 2014 (International Coffee Organization, 2016). More coffee is being consumed but the production can’t keep the pace.

Figure 4. Coffee deficit. Source: International Coffee Organization.

The future of our Latte looks scary, but we can definitely do something about it!

Starting from the problem’s core: CO2 emissions. Every year in the UK more than 2.5 billion disposable cups are thrown away, it requires energy to produce them and energy to get rid of them. So why don’t invest in a cool reusable cup? Or better, if you are a student, you can ask your Uni to introduce a free reusable cup in the welcome kit (I just got mine!).

If you own or work in a coffee shop, try to recycle the coffee grounds! This is a great example of company that produces clean energy with coffee grounds in London.

In the research and governance arena, it is much more to do, the solutions should be diverse and involving all sectors. Some of them are: strengthening the linkages between the actors involved in the supply and marketing chain, research entities and funding organizations; enhancing ecological control on plagues; and breeding for plague and extreme weather resistance.

So now you can go for a coffee with your friends and tell them why they should worry about climate change. Well, after all this writing, I might use a coffee-break ...See you next week!