This Sunday, March 20, at 4:33 p.m. (Peninsula time) spring officially begins, when the equinox occurs, that is, when the length of day and night practically coincide. From now on, the hours with sunlight during the day will be lengthening rapidly, since the Sun will rise each morning more than a minute earlier than the previous day, while, in the afternoon, it will set behind the horizon a minute more. late every day. Namely, each day will last about three minutes longer than the previous one, and this will culminate on June 21, when the day with the most hours of sunshine is experienced.
As far as the weather is concerned, the AEMET has announced that this year spring will be warmer and drier than normal, with an average temperature of 13.6ºC. The Agency states that the months of April, May and June will be “at least” 0.5ºC warmer than usual in the Peninsula and the Balearic Islands. Already the winter that we are now saying goodbye to has been the second driest since 1961. This consolidates the trend towards progressive global warming predicted by all scientific reports due to climate change.
This fact, that is, Each year, the arrival of high temperatures is brought forward, which has visible consequences on nature.. Many plants flower before, but instead they do not do so at the same time as other living beings that depend on them, producing a ‘decoupling’ in the natural rhythms that harm many species. For example, flowers and butterflies no longer come out at the same time, but more and more days apart.
Nature dresses up
In any case, spring is always the season when nature seems to dress up, exhibiting a burst of colors and aromas that show the maximum activity of plants and animals.
The blossoming of almond or cherry trees It is one of the first symptoms of the arrival of spring. The entire plant kingdom joins this burst of energy and, with it, allergies due to the spread of pollen in the air also proliferate, earlier and earlier.
It is also now when they begin to reach the Spanish wetlands and other ecosystems great variety of migratory birds to carry out their reproduction. Swallows and swifts, important insectivores that keep insect populations at bay, have already left their winter quarters to take flight towards the Peninsula.
Ducks, waders and waders (flamingos, herons) and certain birds of prey arrive every year in Doñana and other humid areas of the Peninsula.
Likewise, it is the courtship season par excellence of the brown bearand are also the dates on which the offspring of rabbits, deer, fallow deer, wild boar or mountain goats are born.
Everything obeys a natural design that acts like a clock that regulates the reproductive cycles of the entire animal and plant world. And yet, this gear is beginning to fail due to global warming.
Biological spring begins each year a little earlier
An investigation carried out by Jian Wang, from the Ohio State University in the USA, and by Josep Peñuelas, research professor at the CSIC at the Center for Research and Forestry Applications (CREAF), for the first time he relates the lack of rain and the premature awakening of nature. This study specifically foresees a advancement of biological spring between 1.2 and 2.2 days per decade as a consequence of the decrease in the frequency of precipitation forecast for this century.
Less precipitation means less cloudiness, which gives more hours of sunshine, higher midday temperatures, and cooler nights that advance the cold buildup required for leaf budding. The cocktail of conditions confuses the plants and makes them sprout earlier.
“Although this study talks about climate, and ​​we should not confuse this winter’s weather with climatology, the situation we are experiencing helps us understand how the lack of cloud cover confuses our plants& rdquor ;, he explains Joseph Penuelas.
To carry out the research, the team measured the carbon fluxes of the vegetation, since when the plants wake up they start to carry out photosynthesis and change the carbon fluxes. They also recorded on-site the exit of the leaves and verified on a large scale with satellite images the changes in the greenery of vegetation.
The lack of clouds confuses them
The fact is understandable. If the winters have less and less rain, this means that there are fewer clouds.. Clear skies give strong temperature contrasts between day and night and the day temperature also rises much higher.
In the same way, without the filter of cloudiness, the plants receive solar radiation for many more hours. At night, conversely, the environment cools quickly and freezes easily.
All this confuses the plants because they perceive it as the typical signs that spring has already arrived.: they accumulate the hours of cold and radiation they need earlier and, together with the temperature contrasts typical of spring, they wake up from their winter slumber before time.
“If plants sprout earlier, they start photosynthesising earlier and that affects carbon cycles around the world.. Knowing that the decrease in the frequency of rainfall also affects this natural rhythm is key knowledge to take into account in climate change predictions”, determines Peñuelas.
According to the report, high temperatures and low rainfall cause a decoupling between the flowering season and the flight season of the butterflies to the extent that “the moments of maximum flowering and maximum abundance of butterflies are separated by an average of 70 days” and even more so in dry years.
Similarly, according to the Spanish Society of Ornithology (SEO), the barn swallow advances its arrival in the Peninsula by approximately one month in relation to the middle of the last century. The same trend is observed in other species.
Reference study: https://www.nature.com/articles/s41558-022-01285-w