The IPCC propose solutions in its 5th report on climate change

In Amsterdam from 28 October to 1 November 2014, the IPCC published a final synthesis of its 5th report of evaluation on Climate Change,destined to be read by decision-makers.

The changes are observed on various levels: temperatures, acidification of oceans, melting of glaciers, sea levels rising and the concentration of greenhouse gases (GHG). The changes to come depend on the evolution of GHG emissions and on their concentration in the atmosphere. Four profiles are presented, including two "central" ones with no immediate stabilisation of those emissions on a compatible level with the natural ability of the planet to absorb GHG (RCP4.5 and RCP6.0).

To reduce the vulnerability to climate change, to limit GHG emissions and preserve the chances for a sustainable development, no option is enough by itself. However many factors of success can be mobilized.

Annual emissions are evaluated at 35 GtCO2, meaning 350 GtCO2 injected into the atmosphere per decade. Cumulated GHG emissions of human origin will go from +1 500 GtCO2 in 2010 to +3 000/3 400 GtCO2 in 2100 compared to pre-industry levels (1870).

Main impacts weigh on:

• Water cycle, that will evolve depending on areas, with a distinct contrast of precipitations between humid and dry areas, as well as between humid and dry seasons.
• The average rising of sea levels will vary from +20 to +25 cm by 2050 and from +60 to +70 by 2100, according to the RCP4.5 scenario; knowing that the ocean absorbs 65% of additionnal heat, it will gain 1,3°C more in the first 100 meters and 0,3°C at 1 000m deep, affecting the oceanic circulation.
• Massive extinction of species.
• Food insecurity and constraints on an important part of human activities.

In order to stem this growth and to stabilize the climate at +2°C, significative actions must be taken to reduce GHG emissions and to get associated co-benefits, such as:

• improve energy efficiency and use clean energies;
• reduce pollution emissions into the air, affecting human health;
• reduce energy and water consumption in cities;
• develop sustainable agriculture and forestry;
• protect carbon-stocking ecosystems that bring more services to mankind

Limiting the effects of climate changes is a condition to a sustainable development. The responsibility of pollution emitting countries and their capacity to lead mitigation and adaptation policies to face those impacts, varies. These policies raise the question of justice and fairness.

In order to reduce the vulnerability to climate change, to reduce GHG emissions and preserve chances of a sustainable development, no option is enough by itself. However, many factors of success can be mobilised:

• effective organizations and good governance at all levels;
• innovation and investment in infrastructures and green technologies
• evolution towards more ecological lifestyles and behaviors.

More & rsquo; information http://www.ipcc.ch

Source: NovaSIRHE translated from French