The concentration of CO2 in the atmosphere is measured in parts per million (ppm).
270 was the concentration in the preindustrial era.
350 is considered the ideal to which we should go.
400 is the current concentration.
450 ppm is the level sobrepasaríamos marking the limit of two degrees higher.
At the current rate of emissions, the limit would be reached by 2050.
Video evolution of CO2 level in 800,000 years
The temperature rise since pre-industrial times was + 0,85ºC. Although the pace of the rise in surface temperature has dropped in the last fifteen years (1998-2012) with respect to the average of 1951-2012 (an increase of 0.05 ° C per decade against 0,12ºC ). The IPCC explains that this is due to the attenuation of sunlight by volcanic eruptions and a redistribution of heat in the oceans. Thus conclude that evolution over short periods does not reflect the long-term trend.
Both international agreements such as the IPCC determined that an increase of +2 ° C is the maximum limit that we ought to bring.
The forecast temperature rise by 2100 are among +3.2 and + 6 ° C, if the current rate of emissions continues.
The current sea level rise, changes in precipitation and less fresh water available, among other factors, adversely affect arable land.
In the case of major crops (wheat, rice and corn), in tropical and temperate regions, an increase of 2 degrees Celsius will lead to declines in agricultural productivity around 25%.
EXPONENTIAL POPULATION GROWTH
A person who today is 40 years (1974), has seen the population increase from 4000 to 7000 million, and according to studies is 60 years when share the planet with 11 billion more.
The resource depletion, environmental degradation and high population pressure, is one of the great challenges of the XXI century.
DEFICIT OF THE PLANET
Today, more than 80 percent of the world population lives in countries that use more than their own ecosystems can renew. These countries “ecological debtors” depleting their own ecological resources, or obtain them from others.
Our demand for resources is equivalent to just over 1.5 Lands, and will be 2.5 planets for the first half of this century if we continue at the current pace. If we all lived at the same level as US residents, 4 Earths would be required to sustain the population.
The inability to maintain an ecological debt unlimited scenario, force reducing resource consumption more or less traumatic, depending on the measures taken.
Any exploitation of a nonrenewable resource has a similar behavior. After its discovery increases production, up to the zenith, where it begins to decrease rapidly. Especially hydrocarbons, keep in mind that whenever the sites are inaccessible, requiring more energy for the same amount as before. This means, as shown in the graph, the net energy available after the peak, suffered an almost vertical drop.