2014, the hottest year

By the end of November 2014, the year 2014 was thought to be on track to be one of the hottest, if not the hottest, on record, according to preliminary estimates by the World Metorological Organization. Temperatures for January to October have set a new record. The average global temperatures over land and sea surface were 0.57C above the average of 124.00C for the 1961-1990 reference period.

NASA and National Oceanographic and Atmospheric Administration (NOAA) have since confirmed that the year 2014 is ranked as Earth’s warmest year since 1880.

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2015, Hot year

 

2015 se fait une place au soleil dans le top 3 des 10 années françaises les plus chaudes jamais enregistrées depuis 1880. 10 années qui se situent toutes entre 1990 et 2015.

«Tous les mois de 2015 n’ont pas été chauds. Septembre et octobre ont été plus frais que d’habitude» souligne Mme Berne, climatologue à Météo-France. «Mais ce qui a fait basculer 2015 dans les années très chaudes, c’est novembre et décembre».
Cruel hasard du calendrier, la COP21 s’est tenu au cours du mois de décembre le plus chaud jamais observé en France depuis 1900 : +3,9° par rapport aux valeurs de saison !
En France, l’anomalie de 2015 correspond à une moyenne de 1°C au-dessus de la normale.

Autre impact : la pluviométrie. Toujours selon Météo-France, avec un déficit de 10% sur la quasi-totalité du pays, 2015 se place parmi les 10 années les plus sèches depuis plus de 50 ans.

2015 : plus chaude que 2014 ?

Alors que 2014 venait d’être affublée du titre d’année la plus chaude jamais enregistrée depuis l’ère pré-industrielle (+ 0,92°C par rapport la moyenne 1951-80), 2015 est en passe de lui ravir cette place peu glorieuse. Le franchissement du seuil symbolique de +1°C devrait être franchi. D’autant que les observations montrent que les années soumises au phénomène El Niño, tel que le Pacifique le connait en ce moment, ont toutes atteint sinon dépassé +0,5°C.
Une hausse qui peut désormais paraitre dérisoire quand on sait que le El Niño actuel est l’un des plus puissant jamais observé.

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Large fossil reserves must stay in the ground

According to a scientific report published on the 7th of January in Nature, three quarters of known fuel reserves must be kept in the ground if global warming was not to breach a rise of 2C by the end of the century.

Given the imperatives of climate change, gas explorations in the Arctic, which are estimated to hold 20% of the world’s gas reserves, are incommensurate.

 

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Antarctic: the hidden price of the iceberg

In a worst case scenario, the melting of the entire Antarctic Ice sheet would lead to a rise of sea levels of 57 meters. But with a surface of 12,1 millions Km² that rises of 2,9% every decade since the 1980’s, the Antarctic ice doesn’t really seem to suffer from the climate change. Or does it ?

The Antarctic case shows how complex the climate issue is. Indeed, if the surface of the Ice sheet rises, its volume is dramatically diminishing.

All the Antarctic parts do not react the same way to climate change. In the West, the ice sheet is breaking apart while in the South and the East, it keeps growing. But how can such a phenomenon be explained ?

Jinlun Zhang from the University of Washington, brought an explanation to the current evolution of the Antarctic Ice sheet. According to him, stronger westerly winds around the South Pole can explain 80% of the Antarctic sea ice volume increase in the past three decades. The polar vortex that swirls around the North Pole is not just stronger than before, it has also more convergence meaning it shoves the ice together to cause ridging. The Southern Ocean also becomes colder because of the ice melting which causes runoff. These cold waters boosts the spread of thin ice around Antarctica.

There are land ice and sea ice. Land ice is the result of thousands of years of snow that has become ice over time. Sea ice is made of salted water, it expands during winter months and disappears almost completely in summer.
In Antarctica, the sea ice raises while the land ice reduces. A recent study proved that every year, Antarctica loses between 100 and 300 Giga tons of ice. It has to be reminded that the melting of 360GT per year causes the rise of sea levels of 1mm.

So the Antarctic’s surface increases but its volume decreases !

 

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Biodiversity and climate : The silence of the bees

 

The biodiversity on the planet records 6 000 plants, 40 000 invertebrates and 1 000 vertebrates. This rich biodiversity has been living on Earth for millenniums but for the last 150 years, climate change caused by human activities has been a huge threat for biodiversity.

According to Mark Urban, the author of a survey on biodiversity , “the most surprising is that the risk of extinction not only increased with rising temperatures but also accelerates”. In a +2°C scenario, 5.2% of the world species would be threatened. With +3°C, 8.5% of the biodiversity is endangered. But each region, each species is different. In hot regions, biodiversity loss could be up to 10% whereas in polar areas, biodiversity could increase up to 300%. According to the IPCC, 80% of the species have already been impacted by climate change. If we are currently able to know what will be the consequences of +2°C rise of temperatures, it is far more difficult to anticipate the consequences of a more important temperatures rise, making it harder to implement efficient biodiversity protection policies.

Since the first eras of agriculture, 10 000 vegetal species have been grown by humans. Currently, not more than 150 of them are commonly grown. According to the last Living Planet Report, there has been an average loss by 52% of fish, birds, mammals, amphibians and reptiles populations compared to 1970. It matters deeply because genetic biodiversity is the reason why so many species including human beings have been able to survive and to become more resilient.
The current “colony collapse disorder” is a symbol of this phenomenon. 42% of bees’ colonies in the United States have disappeared. According to Britannic review The Lancet, this pollinators decline could lead to a rise of global human mortality by 3%. This is why our fate is inextricably linked to biodiversity.

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Climate, food security and healthcare

805 million people worldwide suffer from hunger. For the most part, these people live in developing countries. According to the the United Nations Development Program (UNDP), 600 million people could be added to the previous total in 2080 because of climate change. Paradoxically, the main victims of this change are also the least responsible for it.

In just one century, the global temperature rose by an average of 0.75°C. But this trend continues to be on the rise. Climate change has major consequences on water access and agriculture: the decline in agricultural yields, crops destruction by extreme weather events, season shifts and changes, many elements impacting food safety and populations. Implementing adaptation policies is therefore an absolute necessity.

Malnutrition and lack of access to drinkable water are not the only health issues caused by climate change. Heat waves are going to become more and more recurrent, increasing the risks of death, especially among older populations. Some vector-borne diseases like malaria or dengue will spread. Allergies will also become more frequent and more potent because of the spread of allergen plant species and atmospheric pollution.

Developing and industrialized countries will all be impacted but in different ways. The only sure thing is that vulnerable populations will become even more vulnerable. Despite having local specificities, the climate change issue needs a global answer. The climate conference (COP 21) in Paris in December will be the perfect place to find one.

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From extreme weather to climate forecasts

In January 2015, Africa and more precisely Cape Verde, Malawi and Mozambique have experienced unusual heavy rainfalls. Some weather stations have recorded rain levels approaching 400mm in one day. The floodings that occurred caused 300 deaths and 400 000 refugees displaced.
As stated by climatologists, these extreme events are another proof of the climate changes currently occurring on the African continent. Africa is one of the most vulnerable region to climate change: droughts, floodings, heat waves. All these elements make adaptation to climate change one of the most vital stakes for Africa.

Weather or Climate ?

Meteorological data enable us to know instantly the weather forecast. Climate data on the other side is the analysis of data on the long term. That is why extreme weather can happen but extreme climate is highly unusual.

Putting weather observations in perspective on a few decades makes it possible to draw conclusions on the global climate’s evolution.

The sum of meteorological extreme data is part of the bigger picture : climate predictions.

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El niño is back

 

El Niño was expected last year but it was a no-show. It finally happened on March 2015 according to scientists at the National Oceanic and Atmospheric Administration.

El Niño is part of a weather pattern divided in two phases. El Niño is the warm phase. The cold phase of this oscillation is called La Niña. El Niño occurs when Indonesian warm water around Indonesia shifts to the Eastern Pacific. Consequently, temperatures in the Eastern Pacific rise from 5 to 6 degrees Celsius above average. This phenomenon can have dangerous consequences such as thunderstorms, floodings, cyclones or droughts.

The last major El Niño event occurred in 1997-1998 and claimed around 23.000 lives worldwide and caused from 34 to 36 billion dollars in damages. Its effects are felt all around the globe and it “releases a ton of energy and can have a huge domino effect” says Michelle L’Heureux. It can deeply impact agriculture and food security. For example wheat crops in Australia have been particularly affected by El Niño in the past.

Currently El Niño is still weak to moderate. Scientific data shows that the subsurface ocean temperatures in the “Niño 34” area –center of Indian Ocean- has been at least 0.5C above average. El Niño happens later than usual and its odds to continue through the entire summer are 50 to 60% according to NOAA. It means that El Niño is less likely to deeply affect weather conditions. However, 2014 is the warmest year ever recorded despite El Niño’s absence. El Niño means higher temperatures than average because of the warmth transfer from the Ocean up to the atmosphere. Consequently, El Niño makes it more likely that 2015 will beat 2014 record. This should be another incentive towards policymakers to find an agreement at Paris in December 2015 for the COP21.

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The Southern ocean is the true lung of our planet

 

Every year mankind’s GHG emissions total is 10 billion Teq CO. Half of these emissions are stocked in the atmosphere and contribute to strengthen greenhouse effect. The other half is absorbed by carbon sinks: forests and oceans. Oceans absorb almost half of the 5 Gigatons emitted every year and the Southern Ocean absorb half of them by itself. Basically, the Southern Ocean alone absorb 25% of our GHG emissions. That is why it is one of the most important pieces of the global weather puzzle. It explains why so many climatologists and oceanographists have taken an interest in it.

Oceans don’t just absorb carbon dioxide. They also supply oxygen and in great quantities, through photosynthesis by aquatic algae and other organisms. These organisms are called phytoplankton and produce approximatively 60 percent of Earth’s oxygen.

Unfortunately, the more levels of CO2 increase, the more Oceans’ PH drop, leading to devastating global consequences. Oceans’ acidification has increased by 26% since the pre-industrial area, directly affecting marine ecosystems. Equally worrisome, is the fact that as the oceans continue to absorb more CO2, their capacity as a carbon storehouse could diminish. Oceans and particularly the Southern Ocean are of vital interest for climate change mitigation. Undoubtedly they will be tabled for discussion during the COP21 in Paris.

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The unavoidable sea level rise

 

2005, Hurricane Katrina: the flooding of New Orleans killed 18,000 people.

2008, Hurricane Nargis: 150,000 people killed in the Irrawaddy Delta region, also because of flooding.

 While floods caused by extreme weather are occurring more and more often and are growing stronger, the rise of sea level is a phenomenon impacting all the coastlines across the world. Over the last decades, the sea level rose by 2 mm per year, which is 20 times faster than it did for the two past centuries.

 This rise has two explanations: the melting ice and the thermal expansion of water amplified by climate change. IPCC feared a sea-level rise of 98 cm by the end of the century but NASA just reported that a rise of 1meter by 2100 is now inevitable.

 Half of the world population currently lives at less than 200km from the coastline and one in ten people lives at less than 10 meters above sea-level. In France 24% of the coastline is now under the threat of erosion. A phenomenon with many consequences: soil salinization, contamination of drinking water, agricultural land loss, reduction in biodiversity. According to a study published in Nature Climate Change, floods alone could cost up to a trillion dollars every year.

 In addition to the efforts made to prevent the sea level from rising, it is now fundamental to implement adaptation policies. In Bangladesh, 40% of the lands could be flooded, Netherlands has to build new dikes and populations living on islands in the Pacific Ocean may have to flee. All countries will be impacted by this phenomenon but some more than others. Once again the most vulnerable countries are the one which will have to face the most severe consequences. This situation will have to be addressed by the international community at the next COP21 which will take place in Paris.

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