What is global climate change?

In the past few years, we have seen the emergence of several social movements related to climate change, such as "Youth for climate", which intends to raise social awareness of the climate emergency and exert political pressure, and thus mitigate the effects of the environmental crisis.

1 . Climate change evidence

Climate change is defined as a variation in the global climate that affects different climate parameters at different scales.

All emission scenarios projected by the Intergovernmental Panel on Climate Change (IPCC) predict that the carbon dioxide concentration, as well as the average temperature of the planet surface and the sea level, will rise during the 21st century. During the 20th century, temperature increased by 0.6 degrees Celsius and the sea level rose between 10 and 12 centimetres.      

The evidence of human influence on the climate system has increased since the IPCC Fourth Assessment Report. Temperature is expected to increase 1.5 to 2 degrees Celsius, causing new long term changes such as the retreat of glaciers, the melting of polar ice caps, and consequently, a rise in sea level. By 2100, the mean sea level rise would be 10 cm if global warming stays at 1.5 degrees Celsius, and it will continue to rise after 2100.

A priori, ecological systems in small islands, coasts and deltas would be the areas most at risk of flooding.

2 . What causes climate change?

The causes of climate change are natural-environmental, and are exacerbated by human activities related to production and energy use, leading to problems that affect the planet and the socio-economic systems that sustain us. Experts consider it very likely that more than half of the observed increase in average surface temperature from 1951 until 2010 was caused by an increase in the concentration of greenhouse gases (GHG) generated by human beings.

3 . What are the effects of climate change?

The expected effects are negative both economically and socially, and the poorest countries will suffer the worst impact. In a future climate change scenario, we may see shortages of drinking water and food, and an increase in mortality due to floods, storms, drought and heat waves.

Climate change will reduce to a great extent water reserves in areas which currently do not have enough water available, although climate change is expected to increase water reserves in other areas. Furthermore, water demand is increasing due to population growth and economic development, even though in some countries it is decreasing thanks to greater use efficiency.

Despite the consequences of climate change, there are still uncertainties that make it difficult to quantify the magnitude of the effects of climate change. Nevertheless, there is clear evidence showing we must take action immediately.

4 . The fight against climate change

The Intergovernmental Panel on Climate Change (IPCC), with 195 member countries, prepares and publishes assessment reports, special reports and methodology reports on the national greenhouse gases inventories.

Currently, there is increased interest in addressing the negative impact of climate change, and it can be essentially attributed to two international agreements established in 2015:

• The United Nations 2030 Agenda for Sustainable Development, which includes the Sustainable Development Goals (SDGs).
• The COP21 Paris Agreement, the first universal agreement to fight climate change and enable a sustainable future with low carbon emissions. 189 countries committed to keeping global temperature rise well below 2 degrees Celsius above pre-industrial levels and to pursue efforts to limit the temperature increase even further to 1.5 degrees Celsius.

The 2019 climate change summit was held in Madrid (COP25) on the 15th of December, but the results were not as expected by the different social actors.