Permafrost preserves data of climate change throughout history. Studying the Alpine one before it is founded is an investment for the future
Carlo Barbante directs the Cnr Institute of Polar Sciences and teaches at the University of Ca ‘Foscari. From the book, Written in the Ice. Journey into the changing climate, leaving the Mill (pages 232, euro 15) we anticipate some passages dedicated to the wealth of information preserved by the glaciers.
We are naturally very interested in the planet’s climate over the last 10,000 years, a period in which we Sapiens have made use of that enormous wealth of knowledge acquired over the previous 250,000 years. Experience gained in the field, through two long glaciations that have certainly tempered the physique of our ancestors, sharpening their ingenuity, until the arrival of the Holocene climatic Eden, characterized by mild temperatures similar to the current ones.
The only noteworthy event in the last 10,000 years, before the anthropogenic warming recorded after the industrial revolution, was a small abrupt event that occurred 8,200 years ago and has been observed very well not only in Greenland ice cores.
but also in a variety of other paleoclimatic archives including lake sediments, ocean cores, stalagmites, tree rings, as well as in glacier swings in most of the Northern Hemisphere. Today there is a general consensus that the main cause of this cooling event was the eventual collapse of the North American ice sheet in Hudson Bay and the subsequent sudden drainage of some lakes. From then on, a flat calm, or almost.
All this not without effects on the environment, which remained well etched in the memory of the ice. This, in fact, formed over the centuries and millennia through the slow transformation of snow, faithfully records year after year the variations in the atmospheric composition not only of natural compounds but also of those of human origin emitted since the dawn of civilization to produce energy.
and to transform minerals. Let us take the example of the biomass combustion carried out massively by our ancestors. The Earth is an intrinsically flammable planet, as it contains all the ingredients of the so-called fire triangle, the three specific conditions for fire to be activated: the fuel, which in the case of the first inhabitants of the planet is wood; an oxidizing agent, given by the oxygen contained in the air; and the availability of some trigger […].
Fire affects the climate system by releasing carbon that would otherwise be stored in the woody vegetation, contributing to the overall balance of various aerosols and traces of greenhouse gases present in the atmosphere, including the main one’s carbon dioxide and methane. Fire and climate, therefore, influence each other, as environmental conditions are the key factor in the spread of fire, while greenhouse gas emissions from fires also affect the climate system. contributing to the overall balance of various aerosols and traces of greenhouse gases present in the atmosphere, the main ones being carbon dioxide and methane.
Fire and climate, therefore, influence each other, as environmental conditions are the key factor in the spread of fire, while greenhouse gas emissions from fires also affect the climate system. contributing to the overall balance of various aerosols and traces of greenhouse gases present in the atmosphere, the main ones being carbon dioxide and methane. Fire and climate, therefore, influence each other, as environmental conditions are the key factor in the spread of fire, while greenhouse gas emissions from fires also affect the climate system.
Many of the fires that have occurred since the most remote eras have been induced by man, as human beings have always had the need to use combustion for domestic (cooking, hunting, heating), agricultural (deforestation, land use) needs. ) and economic development. Fire and human history go hand in hand. But when did man-made combustion begin to alter the climatic and environmental system in turn in such a significant way as to produce a quantifiable signal in the proxies (indicators, ed.) climatic?
This is a fundamental question that is also answered in the ice crystals of the polar caps where the first signs of fires started by our ancestors are trapped […]. Carbon dioxide has been steadily but slightly increasing for about 8,000 years and methane for 5,000 years. In pre-industrial times, atmospheric methane reached its most recent peak, 10,000 years ago, and concentrations of this gas should have decreased since then had it followed the same pattern as the last four glacial-interglacial cycles.
However, after the last peak, the levels slowly fell for just 2,000 years, then started rising again. This change coincides with the start of the great deforestation for agriculture in Eurasia 8,000 years ago. And the ice retains a clear trace […]. Ice is not only a climatic archive but also a witness to the anthropic impact on the environment and to the great acceleration in the exploitation of natural resources.
The development of new analytical methods for the analysis of new climatic and environmental proxies opens frontiers that until a few years ago were unimaginable in the field of climate sciences and ice cores. Yet the time to explore them could be numbered: glaciers all over the world, including those in the Alps, they are retreating and melting even at altitudes up to 6,000 m above sea level.
The melting rate of glaciers is far faster than our ability to develop new methods of analysis to reveal even the deepest secrets of the climate of the past […]. Since the second half of the 19th century, Alpine glaciers have undergone a general, almost continuous retreat, losing on average 60% of their mass. By the end of the century, according to the most recent simulations, a further reduction in glacial masses is estimated to be between 60 and 90% compared to the current mass. In addition to the well-known consequences in terms of water resources, the environment and alpine ecosystems, the melting of a glacier implies the destruction of its natural archive of information on the climate and the environment of the past.
And just like a burning library, the disappearance of a glacier is an incalculable loss of our cultural heritage and knowledge. It is therefore essential to recover as many ice cores as possible from the Alps while they still exist because once a glacier begins to melt, all the climatic and environmental information that has been stored within it for thousands of years will be lost forever.
To this end, together with an international team, we have recently launched the ‘Ice memory’ research project (www.icememory.it) which aims to drill the most significant mountain glaciers in the world currently at risk of disappearing. in order to preserve the information contained therein and make it available for future generations. At each site, at least two ice cores will be extracted. Of these, the first will be immediately analyzed in specialized laboratories, while the second will be transferred to Antarctica, the coldest place on the planet. It is kept there as in a sanctuary […]. Preserving ice for future generations is a scientific responsibility of our generation, witnessing global warming and damage in high mountain glaciers.
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