Carlo Barbanti directs the Cnr Institute of Polar Sciences and teaches at Ca’ Foscari University. from the book, written in ice. A journey in a changing climatefrom the grinder (pp. 232, Euro 15) expect some passages devoted to the wealth of information held by glaciers.
Naturally, we are very interested in the climate of the planet over the past 10,000 years, the period in which we sapiens have used the vast wealth of knowledge gained over the past 250,000 years. Experience gained in the field, through two tall icebergs that certainly softened our ancestors’ architecture, honing their ingenuity, until the arrival of the climatic Holocene Eden, characterized by moderate temperatures comparable to those of the present.
The only noteworthy event in the last 10,000 years, before the anthropogenic warming recorded after the Industrial Revolution, was a small sudden event that occurred 8,200 years ago that has been well observed not only in Greenland’s ice cores. but also in a variety of other paleoclimate archives including lake sediments, ocean cores, stalagmites, and tree rings, as well as in glacier fluctuations in much 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 abrupt discharge of some lakes. From then on, flat or semi-quiet. Centuries and millennia passed unabated in a monotonous alternation of seasons that allowed our ancestors to quickly pass from nomadic populations of hunters and gatherers to permanent civilizations, with the expansion of the first forms of cities and the emergence of pastoralism and agriculture.
All this is not without effects on the environment that have remained engraved in the memory of the ice. This in fact, formed over centuries and millennia by the slow transformation of snow, faithfully records year after year changes in the atmospheric composition of not only natural compounds, but also those of human origin emitted since the dawn of civilization to produce energy. and metal conversion. Let’s take the example of a large-scale combustion of biomass that our ancestors carried out. Earth is an intrinsically flammable planet, containing all the components of the so-called triangle of fire, which are the three specific conditions for the activation of fire: fuel, of which wood is in the case of the first inhabitants of the planet; combustion agent, given by the oxygen in the air; Availability of some trigger […]. Fire affects the climate system by releasing carbon that would otherwise have been stored in woody vegetation, contributing to the overall balance of various aerosols and greenhouse gases present in the atmosphere, including carbon dioxide and methane. Therefore, fire and climate affect each other, since environmental conditions are the main 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 earliest times were caused by humans, as humans have always needed to use combustion for domestic needs (cooking, hunting, heating), agricultural (deforestation, land use) and economic growth. Fire and human history go hand in hand. But when did man-made combustion begin to alter the climate and ecosystem in a significant way to produce a quantifiable signal in Agents (pointers, so) from my brother? This is a fundamental question also answered in the ice crystals of the polar caps where the first signs of fires started by our ancestors were trapped. […]. Carbon dioxide has remained constant but increased slightly for about 8000 years and methane for 5000 years. In pre-industrial times, atmospheric methane reached its last peak, 10,000 years ago, and concentrations of this gas should have decreased since then had they followed the same pattern of the last four glacial cycles.
However, after the last peak, levels only slowly decreased for 2,000 years, and then started to rise again. This change coincides with the start of large deforestation for agriculture in Eurasia 8000 years ago. The ice retains a clear trace of it […]. Ice is not only a climatic archive, but also a witness to the human impact on the environment and to the significant acceleration of the exploitation of natural resources. The development of new analytical methods for analyzing new climatic and environmental factors opens up prospects that until a few years ago were unimaginable in the field of climate and ice core science. However, the time to explore them can be numbered: glaciers around the world, including those in the Alps, are retreating and melting even at altitudes of up to 6000 meters above sea level. The rate of glacier melting is far faster than we are able to develop new analysis methods to reveal even the deepest mysteries of past climate. […]. Since the second half of the 19th century, the Alpine glaciers have experienced a general and almost continuous retreat, losing an average of 60% of their mass. By the end of the century, according to the latest simulations, the additional decrease in glacial mass is estimated at 60-90% compared to the current mass. In addition to the known consequences in terms of water resources, the environment and the ecosystems of the Alps, the melting of a glacier means the destruction of its natural archive of information on climate and the environment of the past. The history of our mountains and people is surrounded by ice, as if its crystals were the pages of an ancient manuscript.
Like a burning library, the disappearance of a glacier is an incalculable loss of our cultural heritage and knowledge. It is therefore necessary to recover as many ice samples from the Alps as possible while they are still there, because once a glacier begins to melt, all the climatic and ecological information that has been stored within it for thousands of years will be lost forever. To this end, we recently launched, in cooperation with an international team, the research project “Ice Memory” (www.icememory.it) aimed at excavating the most important mountain glaciers of the world that are currently in danger of disappearing, in order to preserve the information contained in it and make it available to 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 transported to Antarctica, the coldest place on the planet. It is kept there as in the sanctuary […]. Preserving ice for future generations is a scientific responsibility of our generation, as we witness global warming and damage in high mountain glaciers.