Emissions of greenhouse gases and climate change

Abstract

Our climate has been undergoing serious changes for decades. The Intergovernmental Panel on Climate Change (IPCC) argues that this global warming is unequivocal and for the most part should be "very likely" to increase concentrations of greenhouse gases (GHG) emissions from human activities.

The total anthropogenic GHG emissions have continued to increase during 1970 to 2010, with larger absolute increases in the later decades of this period. Despite a growing number of policies to mitigate climate change, the annual GHG emissions grew on average 0,4 giga tons of carbon dioxide equivalent (GtCO2eq) (1,3 %) per year from 1970-2000, and 1,0 GtCO2eq (2,2 %) per year from 2000 to 2010 (1).

The total anthropogenic GHG emissions in 2000 came to 40 GtCO2eq / year and the 2010-49 GtCO2eq / year, which show the highest values in human history; 10 GtCO2eq issued in this period were generated directly by the energy (47 %), industry (30 %), transport (11 %) and construction (3 %) (1). Some exceptions to the large emissions of carbon dioxide (CO2) energy use are chemical processes (cement or lime production, metallurgy, etc.) (2).

About half of the anthropogenic emissions of CO2 accumulated between 1750 and 2010 have occurred in the last 40 years; also these emissions from the burning of fossil fuels and industrial processes contributed about 78 % of the total increase in GHG emissions between 1970 and 2010, a percentage similar contribution for the period 2000 to 2010 (1); also the increasing global concentration of CO2 -in a significant part but minor- is caused by changes in land use and agriculture. The increase in methane has been slower since the early 90s, in line with the total emissions (as a sum of anthropogenic and natural sources), which have been nearly constant during this period (3).

Three factors influence the average surface temperature of the Earth:

The first is determined by the development of our star, the Sun, which was 30 % less warm as in our early planetary system. However, today's warming is greater than that in the past, largely through the intervention of mankind.

The second is determined by Milankovitch cycles the most important of which have to do with such an eccentric is the elliptical mapping the Earth in its orbit around the sun varies in cycles of 100 000 and 400 000 years, becoming more or less elongated, sun modifying the maximum distances, which stations are made more extreme. Also this factor ends up being a constant for the Homo sapiens (2, 4).

The third factor is the concentration of CO2 and other greenhouse gases, which may vary by geological factors, such as volcanism, in the course of thousands of years. Now, mankind has made tremendous change in the span of only one hundred years, due largely to anthropogenic forcing a biogeochemical carbon cycle with a consequent increase in the concentration and the average surface temperature (2).

Based on current scientific knowledge, the expected increase in GHG concentrations in the course of the century announces with some certainty that while the global average surface temperature is 14,5 ° C (as has been in the last 12 thousand years, during the Holocene), 2100 would lie between 18,5 and 19°C, which would be a catastrophe for adverse impacts on the availability of natural resources for human economy. Water, air, land and food will be insufficient for a population that will have exceeded 10 billion inhabitants (2).

In the world, economic growth and population remain the most important drivers of increased emissions of CO2 from burning fossil fuels (1) and this increase is one of the causes of global climate change. The contribution of population growth between 2000 and 2010 was more or less identical to the previous three decades, while the contribution of economic growth has increased significantly (1).

Climate change is one of the biggest problems of our time and there is a deep alarm that GHG emissions continue to rise worldwide.

All countries, particularly developing countries, are vulnerable to the adverse effects of climate change and are already experiencing greater effects, including persistent drought and extreme weather events, sea level rise, coastal erosion and acidification of oceans, further threatening food security and measures to eradicate poverty and achieve sustainable development. Thus, it becomes clear that adaptation to climate change is an immediate and urgent global priority.

The global nature of climate change calls for the widest possible cooperation by all countries and their participation in an effective and appropriate international response, in order to accelerate the reduction of global GHG emissions (5).

It is important to remember that the UN Framework Convention on Climate Change provides that parties should protect the climate system for the benefit of present and future generations, on the basis of equity and in accordance with their common but differentiated responsibilities and their respective capabilities, principles and responsibilities that member states already have an obligation in their own legislation.