Causes of climate evolution and observed trends
The last report by the IPCC (Intergovernmental Panel on Climate Change), published in 2007, established that “global GHG emissions attributable to human activities have risen since preindustrial times, increasing 70% in 1970-2004 (…). The essence of the rise in average global temperatures since the mid-twentieth century is probably due in part to increased concentrations of GHG of human origin (…)”. This correlation reaffirms that natural factors (especially solar radiation and volcanic activity) alone cannot explain this phenomenon and confirms, with some degree of certainty, that the essence of the rise in average global temperatures since the mid-twentieth century is due to increased greenhouse gas emissions by activities of human origin.
Global greenhouse gas emissions of human origin
The main sources of greenhouse gases by human activities are:
• the burning of fossil fuels used in transportation, industry, households, and electricity production;
• agriculture and changes in land use, such as deforestation;
• waste disposal;
• use of fluorinated industrial gases.
Total GHG emissions by sector in Europe - 27, 2008
Climate change: predictions and anticipated effects
Trying to predict what the earth’s climate will be like in 2100 is a task that goes beyond the scope of climate sciences. Indeed, it would require making hypotheses about how human societies will develop in order to guess which greenhouse gases will be emitted into the atmosphere over the next century and in what quantities. We would have to try to answer questions like: “How many people will live on earth?”, “What will their lifestyles be like?”, “Will there be growth or recession”, “What kinds of economies will exist?”, “What technologies will be developed?”, “What policies will be put in place to combat climate change?”, etc.
In order to take into account the uncertainties inherent in human societies, a strategy has been adopted to define economic scenarios and study their impact on climate.
To date, these studies originate from a IPCC report known as SRES (Special Report on Emission Scenarios). It contains 4 scenario families: A1 groups together scenarios of rapid growth and strong globalisation (in this family, A1T supposes the use of reduced carbon emission technologies while A1FI assumes a significant development of fossil fuels, for example). A2 also predicts growth scenarios, with less globalisation. B1 imagines more economic lifestyles and increased consumption of weaker material goods in a globalised economy, while B2 proposes the same, but for a regionalised world. None of these scenarios aims to represent how active policy would combat global warming; they are, in essence, scenarios “without intervention”. This strategy is not about predicting the future, but rather aims to project a series of possible futures where none is more probable than the rest.
The ultimate goal would be to guide, in the best way possible, public decision-making.
Climate change is among the greatest challenges facing humanity in the coming years. Rising temperatures, melting glaciers, the multiplication of droughts and floods are all signs that climate change has begun. The risks to the planet and future generations are enormous and require us to decide and act with urgency. Ban Ki-moon, Secretary-General of the United Nations, used these words in a declaration in 2007: “The challenge of climate change, and what we do to address it, will be decisive for us, our time, and our global heritage”. In this way, he underlines the critical nature of policy and legislation decisions regarding the fight against climate change.
Over the last several years, the European Union has committed to this struggle, both internally and internationally, making it a priority that is reflected in climate change policy. In this regard, the European Union has been at the forefront of global action against climate change by committing to reduce CO2 and other greenhouse effect gases at least 20% with respect to 1990 levels by 2020.
Nonetheless, the decisions made at the international and European level should also be put in place at the national level. Thus, France, Spain, and Andorra may adopt plans and legislation to further their role in the struggle against climate changes, especially in the Pyrenees mountain region.