Spring flowers are in full bloom.
As the yellow dust clears, the clear skies and warm temperatures have returned a perfect time for outing.
Cherry blossoms in Seoul this spring bloomed on the 24th of last month, the earliest time since 1922, when the Meteorological Administration began observing cherry blossoms.
The Meteorological Administration analyzed that the average temperature between February and March was high and the flowers bloomed quickly due to the long sunlight.
The official flowering is based on the designated tree in Songwol-dong, Jongno-gu, but now you can see the cherry blossoms in full bloom anywhere other than Songwol-dong.
As the cherry blossoms bloomed, the snow became fun, and some people were concerned about climate change in the flowers that bloomed earlier than expected.
Climate usually refers to the average temperature of 30 years meteorologically.
Until now, the climate value of Korea has used the average temperature of 12.5℃ for 30 years from 1981 to 2010.
Recently, the Meteorological Administration re-announced the climate value, the period from 1991 to 2020, which is the latest average value including last year.
The newly announced climate value is 12.8℃, which is 0.3℃ higher than the last time.
By region, the inland of the central region had the highest rise, and the temperature rose in all four seasons: spring, summer, autumn, and winter.
Although it is a short-term data, the warming trend has remained.
It is not surprising now that as the temperature rises, many side effects appear everywhere.
The world average temperature has already risen sharply by more than 1℃ compared to industrialization, exceeding the range of natural fluctuations, and weather phenomena that threaten our lives such as typhoons, heavy rains, heavy snowfalls and droughts are getting stronger and stronger.
According to the Meteorological Administration, only the damage caused by typhoons and heavy rains last year was KRW 1.255.5 billion.
This is three times more than the average amount of damage in the last 10 years.
Temperatures are also rising or falling extremely over a short period of time, and the difference between the warmest and coldest days in Seoul in January of this year exceeded 30℃.
Do you become hungry as the global temperature increases?
The problem is that not only external meteorological phenomena such as'instrumental image' are deteriorating.
High temperatures also have a big impact on ecosystems.
The ecological system can be broadly divided into producers and consumers, and consumers can be further subdivided into primary and secondary.
It is a form in which secondary consumers consume primary consumers, and you can think of it as a food chain.
It is easy to understand if producers are plants, primary consumers are herbivores, and secondary consumers are carnivores.
In each process, necessary energy is delivered to the next-stage organism, and the organisms use the transmitted energy for metabolism, growth, and reproduction.
Energy transfer efficiency is generally calculated around 10%, but the efficiency decreases as it goes to the upper level.
This is because some of the energy is converted into thermal energy during the transfer process.
Warming affects this nutrient delivery process, which means that the higher the temperature, the less efficient the nutrient delivery.
Recently, an overseas research team revealed that the delivery efficiency is reduced through direct biological experiments.
This is the first time that it has been proved through direct biological experiments other than theories.
The research team observed the nitrogen transfer efficiency (phytoplankton → zooplankton) of plankton under warming conditions for 7 years and published the results.
As a result, it was found that the nutrient transfer efficiency decreased by up to 56% in the pond, where the temperature was increased by 4℃ compared to the surroundings.
In other words, even if you consume the same amount, you only get half the energy compared to the previous one.
Under elevated temperatures, the biomass* itself of phytoplankton and zooplankton also decreased.
*Biomass: The amount of energy the biomass has at a certain point in time.
Humanity, the end consumer, is the biggest hit
Why does high temperature affect energy transfer?
Animals and plants, including us, use a lot of energy to maintain body temperature and metabolism.
However, as the temperature rises, the energy that each living organism uses for such body temperature maintenance and metabolism increases gradually.
Because the metabolic rate increases.
In general, it is known that when the temperature rises by 10℃, the metabolic rate doubles (Q10*).
Naturally, as each step uses more energy than before, the amount of energy to be transferred to the next step naturally decreases.
Humans are at the highest of the ecological pyramids.
As mentioned earlier, the efficiency of nutritional delivery decreases as it goes from producer to primary consumer and from primary consumer to secondary consumer.
Since this study is the nutrient transfer efficiency between plankton, the lowest level of the ecological pyramid, it is difficult to accurately quantify what effect it will have on us, but at least it can be predicted that the efficiency will be lower than the transfer efficiency between plankton.
*Q10: A measure of the degree to which biological processes vary with temperature.
Food Difficulty Problem
If so, wouldn't it be possible to eat more?
It's not a simple matter.
This is because nutritional delivery efficiency is not the only loss as the temperature rises.
Currently, Korea uses rice and barley as staple foods.
According to the National Institute of Food Science and Technology, the fields are relatively stagnant, but the number of paddy fields where rice and barley can be grown is rapidly decreasing (see figure).
In fact, Korea's food self-sufficiency rate, which includes rice, barley, and soybeans, has also declined steadily in recent years.
The food self-sufficiency rate for the last five years is showing a marked decline. The most recent data, 2019, reached a record low of 45.8%.
It is threatened by a stable supply of food, which is 9.6% below the target of 55.4% in 2022.
Experts said, "Climate change has reduced the cultivation area, which is affecting agricultural production," and said, "If technological developments such as variety improvement cannot keep up with climate change, it is difficult to guarantee production in the future."
Since this phenomenon is not unique to Korea, importing food from abroad may become more and more difficult in the future.
If climate change continues with the same trend now, in the 2050s, compared to 2010, summer is about 20 days longer and winter is about 30 days less.
In the RCP 8.5 scenario, where efforts for climate change are hardly made, by 2100, most regions of Korea, except for the Gangwon-san region, will change to a subtropical climate.
There is an urgent need for efforts to slow climate change along with the development of science and technology that will pursue the climate for a stable supply of food.
We should also be wary of the'instrumental statues' caused by climate change, but if we consider these additional effects, our future impact may be greater than previously thought.
<References>
Diego R. Barneche, Chris J. Hulatt, Matteo Dossena, Daniel Padfield, Guy Woodward, Mark Trimmer, Gabriel Yvon-Durocher, "Warming impairs trophic transfer efficiency in a long-term field experiment", nature (2021) 592, 76–79, doi.org/10.1038/s41586-021-03352-2