Global warming is a reality.

The huge fires in Canada, Greece during the summer of 2023, the floods also in Greece but in many other countries testify to this. No one denies that rising temperatures is a reality and the majority of scientists and in particular the IPCC (Intergovernmental Panel on Climate Change) attribute this change to increasing greenhouse gas emissions. These gases decrease the reflection of sunlight towards space and contribute to increased temperatures.

Several scientists, Fourier in 1824, Tyndall in 1860, Arrhenius around 1900, showed the increase in temperatures as the concentration of greenhouse gases increased. The main greenhouse gases are carbon dioxide, methane and nitrogen compounds.

Around 1970, environmental concerns became increasingly important. The first Earth Summit will take place in Stockholm in 1972 and will give birth to the United Nations Environment Programme (UNEP). Earth's summits have been meetings for every 10 years since They are dedicated to sustainable development.

COPs (Conferences of the Parties)

At the Earth Summit in Rio in 1992, a "global partnership" to combat global warming was launched. From 1995, each year a Conference of the Parties, bringing together political leaders and NGOs, will be held to accelerate the fight against global warming. The 1997 Kyoto Protocol (COP 3) illustrates this orientation towards a strategy for reducing greenhouse gases (GHGs).

COP15 in 2009 in Copenhagen, despite the presence of the top leaders, will be a failure, United States and China failing to reach an agreement. But this failure will probably lead to the success of COP21 in Paris in December 2015 because the approach will be different: each country announces the efforts it is willing to make to reduce its emissions. This agreement, ratified by 191 countries, considers a share of climate change inevitable, despite all efforts to reduce GHG emissions. It sets a goal: to keep the rise in global warming below the two-degree limit (or even 1.5 degrees above the pre-industrial level).

The 28th UN Climate Conference (COP28) was held in Dubai, United Arab Emirates, from 30 November to 12 December 2023. After laborious negotiations, a draft agreement calling for a transition from fossil fuels was approved by countries around the world. This text calls for the abandonment of fossil fuels with the aim of achieving carbon neutrality in 2050. This is the first time in the history of the UN climate conferences that all fossil fuels are recognized as largely responsible for climate change.

Eight years after the signing of the Paris Climate Agreement, COP28 drew up a first global review of the commitments made by States, set a new course for climate action in countries and tried to limit the rise in temperatures to 1.5°C. Financial assistance has been provided to developing countries affected by climate change.

COPs, useful or useless? Many denounce insufficient or too slow progress in combating climate change. But the possibility of bringing together all environmental stakeholders every year is a success. Nearly 100,000 people were present in Dubai.

Energy transition

The call for an energy transition "out of fossil fuels" is a very important step. But the challenge is immense

Our energy needs are 80% covered by coal, oil and natural gas. In China and India more than 70% of electricity needs are covered by coal. Oil remains the main source of energy for transport: petrol and diesel for cars, diesel for trucks, kerosene for aircraft, fuel for ships. In addition, plastics, another major source of environmental concern, are produced from oil.

Replacing these energy sources will not be easy. "Decarbonated" energy sources that do not emit greenhouse gases are relatively numerous (mainly hydraulic, wind, solar and nuclear) but currently cover only 20% of the needs

Certainly the increase in the share of wind and sun in the energy mix for 20 years is impressive. In several countries, nearly half of electricity is now supplied by renewable energies (hydraulic, wind, sun)

But wind turbines and solar panels require raw materials whose availability can be limited and extraction can be a source of pollution: aluminium steel, silicon, copper for solar panels, steel, cobalt or nickel, rare earth metals (neodymium, dysprosium, samarium) for wind turbines In the same way, the electric car, which replaces the thermal car, which consumes petrol or diesel, is equipped with a battery which requires many metals, in quantities much higher than those required by a thermal car.

Wind and solar also require considerable surfaces. A large part of the wind turbines or solar panels should be covered to obtain a significant fraction of our electricity. A nuclear power plant requires 100 to 1000 times less space than a wind farm.

Hydraulic, wind and solar will not be able to cover all our needs. Nuclear power can cope with some of our electricity consumption. However, the risks of accidents and the problem of waste management face a part of the population. Relaunching nuclear power will require a lot of pedagogy and communication.

By way of conclusion

COPs are useful. Experts believe that without the COPs, the projected increase in global temperature in the coming years would have been even higher than current expectations. COP 28 was the beginning of a fossil release. But their replacement with decarbonized energy remains a huge challenge