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Climate change: changing the invisible hand of nature and society

  The time has come for humanity to face the test of the climate crisis.
  The global climate has been changing, so why is there a climate crisis? The point is that the pace of climate change has accelerated dramatically.
  Taking the UK as an example, a climate study two years ago indicated that “the UK may experience high temperatures above 40°C in the next few decades, but it is unlikely”. However, only two years later, the high temperature of 40.3 ℃ has appeared in the UK.
  The extreme weather that occurs frequently around the world is a prominent manifestation of accelerated climate change.
  According to the “State of the Global Climate 2021” report released by the World Meteorological Organization, in June and July last year, heat waves and wildfires swept across western North America; cold waves and heavy snowfall raged in North America, Russia and Spain; the frequency of abnormal precipitation became higher and higher, followed by The resulting floods occurred in Zhengzhou, China, western Germany, eastern Belgium, and New South Wales, Australia; South America was affected by drought, and water resources were once short, threatening the survival of local people.
  According to the “Biodiversity and Climate Change” report released by the United Nations Environment Programme, climate change has become one of the main threats to the earth’s biodiversity.
  The most important observational indicator of the impact of climate on organisms is temperature.
  Combing the past history, the five mass extinctions that have occurred in the history of the earth, although the direct causes are different from meteorite impact, the advent of ice age, volcanic eruption, plate migration, but most of them are affected by changes in temperature. The asteroid that caused the extinction of the dinosaurs hit the earth, and the more important impact was that the impact raised dust, obscured the sky, and brought a long global winter.
  Ecology is a complex system involving each other. Small changes in temperature indicators will trigger an unpredictable butterfly effect between species. Some phenomena are being measured and studied, but many more, and their potential impacts, are still hard to predict.
critical high temperature

  Of all the extreme climate changes, the most widespread and most concerned by scientists is the phenomenon of global warming.
  The State of the Global Climate 2021 report shows that the global average temperature in 2021 is about 1.11 (±0.13) degrees higher than the pre-industrial average from 1850 to 1900. The seven-year period from 2015 to 2021 was the seventh warmest on record. In 2020, the global shutdown caused by the new crown epidemic has reduced the rate of carbon dioxide emissions, but the rate that year is still higher than the average rate of the past decade.
  This climate report mainly focuses on the dimensions of greenhouse gas concentration, sea level, ocean heat content, ocean acidification (referring to the tendency of the ocean to gradually reduce the pH value after absorbing carbon dioxide in the atmosphere), and glacier changes. Changes in the state of the earth brought about by warming.
  Observations of these indicators paint a more pessimistic picture of the future. The data show that the rate of sea level rise has doubled in the past 30 years, accompanied by the massive collapse of glaciers around the world. In mid-August last year, Greenland experienced an unusual glacial melting event, and the summit station at an altitude of about 3,216 meters, the highest point of the Greenland Ice Sheet, experienced its first rainfall ever.
  Behind the warming, more importantly, the survival of animals and plants is facing a huge impact.
  Every creature has a different temperature comfort zone. For example, the suitable temperature for the human body is 16-25°C, while the ectothermic animals have no internal temperature regulation system and will adjust their body temperature with the help of the external environment. If the global climate changes too fast, it will threaten the survival of some organisms.
  In 2014, off the west coast of North America, millions of sea stars of at least 20 species died suddenly over a period of months. The researchers believe that rising sea temperatures, beyond the starfish’s comfortable range, activating disease in their bodies — heat stress that weakens an organism’s immune system — is a major cause of this mass die-off. In addition, scientists who study marine diseases have also found that rising water temperatures exacerbate the diseases of marine life such as lobster and abalone.
  On the other hand, rapid changes in climatic conditions have changed many ecological laws on a global scale. Conservation biologist Saul Hansen, author of “The Adventure of Life”, concluded that there are two major trends in the adaptive changes of organisms: first, species are advancing toward the poles, those in the northern hemisphere are moving toward the north pole, and those in the southern hemisphere are moving toward the North Pole. One goes in the direction of the South Pole; two, moves up the slopes of mountains, ridges, and other terrain.
Species that have interacted with each other over a long period of time react differently to climate change, which brings complex changes and mismatches.

  And not only do animals migrate, but plants also move, even faster than many animals.
  The U.S. Tree Census produces an annual survey that counts, measures, and identifies saplings and adult trees in forest lands across the United States. Yearly reports since the 1980s show that the geographic center of many tree species is gradually moving north, and more The geographic center of the many trees moved westward, chasing the rain.
survival of the fittest

  Are the consequences of a warming climate necessarily bad?
  There was a time when people thought that warming the planet was a good thing. As early as 1896, Swedish scientist and Nobel laureate Svante Arrhenius (who proposed that the consumption of coal and gasoline would increase the concentration of carbon dioxide in the air, thereby increasing the surface temperature), optimistically believed that Rising temperatures are a good thing, at least for crops, which can increase crop yields and avoid ice ages.
  Some people still think so, because rising global temperatures have indeed expanded the cultivation of some crops and also increased the sugar content of some fruits, such as apples. But at the same time, pests and diseases also moved northward.
  On the other hand, different species have different rhythms of adaptation and adjustment to temperature changes, which will cause unpredictable compound impacts on the ecological chain.
  One consequence of warming is that springs and summers are longer and winters are shorter. Plants will adjust accordingly to these changes, but animals often do not respond to temperature. In many cases, they rely on light. This will cause a time difference in the ecological chain. For example, the flowers bloom before the arrival of the worms, which means less time for worms to eat pollen and nectar, which directly affects the number of their offspring, which in turn affects the species they are associated with. Most at risk are species that rely on a single resource or relationship and are less able to adjust and adapt.
  In general, species that have interacted with each other over time have responded differently to climate change, leading to complex changes and mismatches.
  In the era of volatile climate and environment, species evolution has once again returned to the way forward in Darwinian sense: survival of the fittest.

  Rising temperatures are a matter of how organisms allocate their time and energy. For example, trees cope with heat by increasing their respiration rate. In hot weather, African wild dogs cut down on daytime hunting, and tropical ants forgo the overheated foraging route through the rainforest canopy.
  However, this adjustment often brings some side effects. Lizards, for example, are cold-blooded animals that regulate their body temperature by basking in the sun, but if it’s too hot, they will hide from the sun, and if they retreat to the shade for too long each day, reproduction will decrease over time.
  In addition, animals have another strategy to deal with climate change: migration.
  At present, there have been as many as tens of thousands of cases of climate-driven migration of living areas observed by humans. Scientists estimate that 25% to 85% of all species are in the process of migration. According to data from Saul Hansen in his book, 37 species have moved an average of 45 kilometers north in just 4 years on a stretch of Northern California coastline in recent years, including barnacles, sea cucumbers, snails, crabs , seaweed, bottlenose dolphins, etc.
  The impact of climate change on animals is also reflected in the acceleration of the process of biological evolution. In Scotland, the spotted wood butterfly develops larger wing muscles to fly farther north; in Finland, as the snow cover decreases, the brown owl has a survival advantage, rather than the grey owl, The occurrence rate is higher.
  Species that were able to adapt to extreme weather were more preserved. For example, where hurricanes are common, lizards often have larger toe pads, while aggressive spiders can survive storms.
climate change humans

  From the perspective of the earth’s ecology, the climate is always changing. This is a common and natural phenomenon. However, the formation process of the climate “face change” we are currently experiencing is controversial. There are two main viewpoints:
  one viewpoint It is believed that the current global warming is in fact part of the natural cycle of the earth’s climate change. For example, geologist and Swiss Chinese Xu Jinghua believes that the current global warming and humidification trend is a natural trend after the earth breaks away from the Little Ice Age, which is a good thing for human beings.
  Another view is that human activities have strongly altered the climate and geography; in particular, the burning of fossil fuels has contributed to global warming.
  Regardless, climate change has been a powerful driver throughout human history, profoundly shaping human society. However, many times it does not intervene in our lives in a direct way.
  In Xu Jinghua’s book “Climate Creates History”, he proposed that “population migration in prehistory and history is caused by cyclical changes in climate”. He even found a more direct link between climate and human history: for example, during periods of global cooling, peoples in marginal arable areas, such as Indo-Europeans, Germans, northern Asians, etc., had to look elsewhere for more fertile land; and in times of global warming, overpopulation and greed become the motives for conquest and colonization. This period saw the expansion of global colonialism.
In Xu Jinghua’s book “Climate Creates History”, he proposed that “population migration in prehistory and history is caused by cyclical changes in climate”.

  According to his research, the impact of climate on human society is also reflected in demographics. During the three hundred years from 1000 to 1300 AD, the population of Europe continued to grow, but since the beginning of the Little Ice Age, the population decreased significantly in the first half of the 14th century. After experiencing the great plague and famine, the overall population growth was quite slow. In China, the main reason for the downfall of the Ming Dynasty was that the 8-year drought caused famine and led to peasant uprisings. At that time, the Ming Dynasty was in the coldest stage of the Little Ice Age, and the fertile Central Plains became a dust basin.
  Scholars who study climate and human history frequently refer to the link between the fall of ancient Rome and climate change. For this reason, scholars also put forward the theory of “ancient Rome’s optimal climate”: the expansion of ancient Rome, in the few hundred BC and the first few centuries AD, happened to be in a warm, humid and stable period. In the climate; the optimal climate not only expands the scope of cultivation, but also increases the productivity of the land, allowing the population to expand outward.
  However, around 150 AD, the “climate optimum period of ancient Rome” was coming to an end, the climate began to dry and cool, and the national fortune of ancient Rome also declined, beginning three centuries of turmoil and chaos.
  By the time of Justinian, the earth entered the stage of the “Late Ancient Little Ice Age”, and the climate became extremely cold. People at the time wrote a report on “A Year Without Summer”, in which they wrote: “The body at noon has no shadow, and the most fiery heat turns into an exceedingly mild weakness. This is not a brief solar eclipse, but at least An eclipse that lasted a whole year…we had a winter without storms, a warm spring, no hot summer.” Bad weather conditions, which led to crop failures, exacerbated the plague.
  But climate does not act directly on humans, causing civilization to collapse. In the words of Kyle Harper in The Fate of Rome: Climate, Disease, and the End of Empire, “The tension between human skill and nature builds up until a later point in time is abrupt. freed”. It is intertwined with economy, society, politics and ecology, so it is quite troublesome to study the causality between natural climate and human society; not only that, it is difficult enough to study the climate itself, and human beings can even accurately predict The weather hasn’t been very good yet.
  Ecosystems are complex, and changes in a single factor can cause a chain reaction like the butterfly effect, and precise measurement is difficult. From the archaeological point of view, it is the same temperature rise, the same species, which survived the more severe climate change, but suddenly disappeared later when the climate change was less severe. This cannot be explained by the single factor of climate change. .
  The Earth’s climate will continue to change, and as it has throughout its history, the Earth will always be habitable for certain creatures. Next, it is time to seriously consider whether it is still suitable for human habitation and how humans should adapt.

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