Climate change is the global variation in the Earth’s climate. This variation is due to natural causes and man’s action and occurs on all climatic parameters: temperature, rainfall, cloudiness, etc., at very different time scales.
At present, there is an almost generalized scientific consensus around the idea that our mode of energy production and consumption is generating a global climate change, which will cause, in turn, severe impacts both on the Earth and on socio-economic systems…
As early as 2001, the Third Assessment Report of the Intergovernmental Group of Experts on Climate Change (IPCC) indicated that numerous pieces of shreds of evidence of the existence of climate change and the impacts derived from it are accumulating. On average, the temperature rose by about 0.6 ° C in the 20th century. The sea level has risen from 10 to 12 centimeters, and researchers believe this is due to the expansion of increasingly hotter oceans.
The Synthesis Report of the Fifth Assessment Report of the IPCC, published in November 2014, concludes that “human influence on the climate system is precise and increasing, and its impacts are observed on all continents. Climate change will increase the likelihood of severe, widespread, and irreversible impacts on people and ecosystems in the slowdown. However, there are options for adapting to climate change, and rigorous mitigation activities can make the impacts of climate change remain at a controllable level, creating a clearer and more sustainable future. “
Climate change affects us all. The potential impact is enormous, with predictions of a lack of clean water, significant changes in conditions for food production, and an increase in death rates due to floods, storms, droughts, and heatwaves. The Synthesis Report confirms that “climate change is observed throughout the world and that the warming of the climate system is unequivocal. Since the 1950s, many of the changes observed have been unprecedented in the last decades to millennia, and the impacts of climate change have already been felt in recent decades on all continents and oceans. “
Climate change is not only an environmental phenomenon but one with profound economic and social consequences. The poorest countries, which are least prepared to deal with rapid changes, will suffer the worst consequences. The 2014 Synthesis Report clearly states that “many risks are particularly problematic for least developed countries and vulnerable communities, given their limited capacity to cope with them. People marginalized in social, economic, cultural, political, institutional or other spheres are especially vulnerable to climate change”.
Said Synthesis Report states that “to limit the risks of climate change truly, it is necessary to substantially and sustainably reduce greenhouse gas emissions. And to the extent that mitigation reduces the rate and magnitude of warming, it stretches the time we have for adaptation to a given level of climate change, potentially by several decades. “
Consequently, although uncertainties do not allow the predicted climate changes to be quantified with sufficient precision, the information validated so far is sufficient to take immediate action under the so-called “Precautionary Principle” referred to in Article 3 of the Framework Convention on Climate Change.
WHEN DID MAN BEGIN TO INFLUENCE CLIMATE CHANGE?
Experts coincide in pointing to the Industrial Revolution as the turning point when greenhouse gas emissions released into the atmosphere began to skyrocket. It must be remembered that the Industrial Revolution was born out of many other small revolutions: agricultural, technological, demographic, means of transport, finance … which gave rise to a new model of production and consumption.
From that moment, the population growth (in 1750, there were less than 800 million inhabitants on Earth, today we are more than 7,500 million), increasingly excessive consumption of resources, the increase in the demand and production of energy obtained mainly through fossil fuels … they have caused the planet to enter what part of the scientific community has called the Anthropocene: the new geological era motivated by the impact of human beings on Earth.
The main result has been the increase in the global temperature of the planet, which has increased by 1.1 ° C since that period, although it is estimated that at the end of this century, the thermometer may increase, even more, fulfilling the commitments to reduce it.
CONSEQUENCES OF CLIMATE CHANGE
How does climate change affect us? This global increase in temperature has disastrous consequences that endanger the survival of the Earth‘s flora and fauna, including humans. Among the impacts of climate change, the melting of the ice mass at the poles stands out, which in turn causes sea-level rise, causing flooding and threatening coastal shores – even small island states are at risk of disappearance -.
Climate change also increases the occurrence of more violent weather events, droughts, fires, the death of animal and plant species, the overflowing of rivers and lakes, the appearance of climate refugees, and the destruction of livelihoods and economic resources. Especially in developing countries.
What is climate change?
According to the United Nations Framework Convention on Climate Change (UNFCCC), this is understood as a climate change attributed directly or indirectly to human activity that alters the composition of the world’s atmosphere and adds to the natural variability of climate observed over comparable time periods. On the other hand, the Intergovernmental Panel of Experts on Climate Change (IPCC) defines it as any change in the climate over time due to natural variability or as a result of human activities.
From the meteorological point of view, climate change is the alteration of the prevailing conditions. External processes such as the variation of solar radiation, variations of the Earth’s orbital parameters (eccentricity, the inclination of the Earth’s axis with respect to the ecliptic), movements of the Earth’s crust, and volcanic activity are factors. that are of great importance in climate change.
What is the greenhouse effect?
Greenhouse gases effectively absorb infrared radiation emitted by the Earth‘s surface, by clouds, and by the atmosphere itself due to the same gases. The atmosphere emits radiation in all directions, including downward toward the Earth’s surface. In this way, greenhouse gases trap heat in the surface-troposphere system. This is called the natural greenhouse effect.
Atmospheric radiation is closely linked to the temperature of the level at which it is emitted. In the troposphere, in general, the temperature decreases with altitude. In fact, the infrared radiation that is emitted into space originates at an altitude whose temperature is, on average, -19 ° C in equilibrium with the net incoming solar radiation, while the surface of the Earth remains at a very average temperature. higher around + 14 ° C.
An increase in the concentration of greenhouse gases leads to a greater opacity of the atmosphere and, therefore, effective radiation into space from a higher altitude and at a lower temperature. This generates radiative forcing, an imbalance that can only be compensated for by an increase in the temperature of the surface-troposphere system. This is the accused greenhouse effect.