The latest Summit on Climate Change (COP21) has ended with an agreement approved by 195 countries. For the first time, it establishes an atmosphere of commitment to reduce emissions of greenhouse gases from burning fossil fuels in order to limit the associated global temperature increase. If the agreement is ratified and developed, this will be the beginning of the end of the era of coal and oil.
Just in case we fall into the temptation of thinking that this is a new thing, in the early nineteenth century, Fourier, a mathematician and physicist, understood that the Earth’s surface temperature is higher than that of an identical planet without atmosphere effected by gases such as carbon dioxide or methane. These gases return to the surface part of the longwave radiation emitted by the Earth, as happens in a greenhouse.
At the end of the 19th century, Arrhenius, physicist and chemist, calculated how much the global temperature could change if the concentration of carbon dioxide doubled. Since then, concentrations of this gas have increased from 280 to 400 ppb (parts per billion), probably the highest level in the past 800 millennia.
Today, scientists no longer debate whether there is a climate change in progress associated with emissions of greenhouse gases produced by human activities; it is known. The temperature increase since the late nineteenth century is unequivocal and more than half of the increase since 1950 is due to manmade emissions.
The Intergovernmental Panel on Climate Change (IPCC) has the mandate of the United Nations (UN) to regularly report on the state of the art in scientific understanding on climate change, the future risks and opportunities and challenges of adaptation and mitigation.
The Paris Agreement, supported in the latest IPCC report for 2013-2014, represents a milestone in the adoption of future commitments to tackle one of the biggest challenges of our time. The international acceptance of this agreement represents an acknowledgement by 195 nations that man is changing the climate. Perhaps the first benefit of this summit is to help eliminate futile disputes about this reality in the media.
Climate refugees
The impacts of climate change are underway. Both changes in the average climate and the occurrence and intensity of extreme cases, droughts, floods and changes in the cryosphere or sea level affect ecosystems. And that’s not all. These changes already affect population shifts and instability associated with limited access to water and food. The conflict in Darfur or Syria, for example, meet some of these ingredients. Society is vulnerable to climate change, particularly in areas where geographic exposure, infrastructure, inequality and lack of resources make it difficult to adapt to hostile conditions.
If greenhouse gases continue to be emitted, it will increase the risk of severe impacts on an ongoing and irreversible way. The risks are greatest in the most vulnerable areas of the planet, with the poorest economies. If the committed measures are not taken, the temperature could have risen by the end of the century to between 4 and 5°C above preindustrial levels.
This will affect biodiversity and our society as we know it, health, infrastructure, it will exacerbate poverty in some regions, inequality with others, it will cause migrations and social disturbances. In the coming decades, some islands will simply disappear off the map as a result of rising sea levels.
The agreement of Le Bourguet- town in which the COP21 was held – adopted a joint position and provides that the richest countries, whose development has produced past emissions, must provide funding and contribute to technological development in poor countries in their adaptation to the consequences of climate change and limit their own emissions.
Developing countries have to transform their energy model before developing systems dependent on coal and oil. India is in the spotlight in this regard and China is an example of growth in renewable energy.
The inheritance of cumulative emissions
The future rise in temperature will be roughly proportional to the amount of carbon emitted since the nineteenth century, so any mitigation plan to try to limit warming at the end of the century is subject, against the clock, to the legacy of accumulated past emissions. In this respect, action should begin as soon as possible.
Refining the future temperature change to less than 2°C compared to the nineteenth century is possible, but requires us to drastically reduce the burning of fossil fuels by 2050. These actions will be a social challenge and technologically difficult and expensive.
Doing nothing will be more expensive.
From the Cancun summit in 2010, the aim was to limit future temperature increase to 2°C. French diplomacy and a more proactive political climate by the United States and China in the Copenhagen summit in 2009 have led to the latter agreement being more ambitious.
A limit below 2°C and a maximum challenge in no more than 1.5°C is set. This could mean the difference between the lands inhabited by million of people being above or below sea level. It is argued that to not exceed 2 degrees emissions should cease by 2050; to reach 1.5°C they should stop by 2030.
But the reality is that we still live on fossil fuels and to reach this agreement, each country has had to submit its first voluntary proposal of its emission reduction determination. If applied, the estimates point to a reduction of warming between 2.7 and 3.5°C above pre-industrial levels; therefore, far from the target of 1.5 to 2°C.
This initial stake is not as ambitious as it would be desirable, possibly because the agreement has tried to reconcile the participation of a large number of countries more than the audacity in reduction targets. In any case, to compensate, the document proposes a procedure for monitoring by the UN which will verify if nations fulfill their promises every five years from 2018 and also allow nations to modify, upwards, their reduction emissions commitments. Countries will apply their policies to reduce emissions from 2020.
The end of the fossil fuel era
The agreement was adopted by consensus but must still be ratified. This will be done in April 2016 at the UN headquarters in New York. The agreement will enter into force if ratified by at least 55 countries representing more than 55% of emissions. If we start on this road, we could be facing the end of the fossil fuel era.
In any case, much of climate change is inevitable and it is underway as a legacy of past emissions and technology and the current energy model. Adaptation and mitigation strategies will be required as well as investments in research and promoting the development of new technologies not based on fossil fuels.
On a global level, investment in energy and energy infrastructure will be enormous but the additional cost of moving to clean energy can be a relatively minor part of the total. With effective implementations, growth and sustainable economic development can be promoted and perhaps also less geopolitical dependence on oil supplies.
Reducing emissions is easier in some industries than others. The decline in deforestation, energy efficiency, power generation or construction are easier to move to a different model than aviation, transport and agriculture. Energy efficiency, renewable energy and nuclear energy are fields that are open to large developments.
Monitoring the Paris Agreement does not guarantee the problem will be solved but provides the framework to reach a revised, monitored and controlled procedure. If we continue in this way, the Paris commitment climate could change the world as we know in a few decades.
This in an extract from the original text which was published on the website of Fundación madri+d
Fidel González Rouco
Co-author, Lead autor, of the 5th IPCC report
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