Earth's climate system brings the heat with seven months of record-breaking temperatures
October, November, December, January, February, March and now April – each month in the past year has been hotter than the last. The past seven months have been the hottest in recorded history. That’s only two centuries’ worth of data. But in those two centuries abnormal months have been haphazardly spread across time. This has changed. Data from Nasa shows that average land and sea temperatures for April were 1.11°C hotter than they should be.
That increase is part of a dramatic shift in recent years. Imperial Germany was battering its way into France the last time a month broke its cold record. Until this millennium dawned temperature records have been set at an increasing rate. When 2005 set the record for the hottest-ever year, it had been eight years since 1998 claimed that honour. But it was surpassed five years later by 2010. Four years later it was 2014. The next year it was 2015. And Nasa projections show that 2016 will continue the trend. The last three months have been hotter by the biggest margin ever.
Jeffrey Sachs, director of Columbia University’s Earth Institute, has said this new trend shows the Earth’s climate system is having “a complete blowout”.
Normally, the world warms and cools over long time periods. This means the temperature difference between months is measured in a hundredth of a degree. April was 0.24°C hotter than April 2010 – the previous record holder, which was 0.12°C hotter than its 2007 cousin. February and March have similarly abrupt increases. In December, the North Pole was an average 0°C, 30°C hotter than it normally is.
Most scientists – such as those at the United Kingdom’s Meteorological Office – agree that a strong El Niño has driven much of the recent record-setting. This phenomenon quickly warms the Pacific Ocean. That leads to drought in the southern hemisphere and floods in the other half of the world. But it is not the strongest El Niño on record. That achievement falls to its 1998 predecessor.
In November, the World Meteorological Organisation said that the five years until then were the warmest such period in recorded history. This was mainly down to the ever-increasing levels of carbon dioxide in the atmosphere, it said.
Last year, the Mauna Lao Observatory in Hawaii tracked concentrations passing 400 parts per million. This is the first time this has happened in human history. That means more things in the atmosphere to trap and reflect heat. Unable to head back into space, heat is now stuck inside the Earth’s atmosphere. Most of that heat goes into the oceans, according to the Intergovernmental Panel on Climate Change, and that unlocks all sorts of problems.
The Pretoria-based Council for Scientific and Industrial Research says a 2°C increase in average global temperatures means up to a 6°C increase in temperatures in South Africa, this century. That shifts rainfall – the country’s biggest constraint to farming and development. Most of the country will get drier and take on the characteristics of the Karoo. Aloes and sheep will be the sole crop. Where rainfall does increase – in parts of KwaZulu-Natal, Mpumalanga and Limpopo – it will come in shorter and heavier spells. That will cause regular flooding and destroy crops.
To stave-off this future, South Africa – and nearly 200 other world governments – signed the Paris Agreement at COP21 late last year. This put countries on the same page: to ensure average temperature increases do not exceed 2°C this century.
Researchers at various organisations, such as the influential Grantham Research Unit on Climate Change, say it is too late to reach that target.
That takes the world into unchartered territory: too many things start changing for computer models to fully predict the fallout. The canary to that scenario is already screaming, with islands in the Pacific being swallowed by swirling waves. Africa, a minimal emitter of carbon, will be hard-hit.
South Africa might be slightly better off thanks to more wealth, meaning people can survive climate shocks such as food price hikes, but the climate is already shifting. The country is already more than 1°C hotter than a century ago. That has already shifted rainfall and made planting crops a less-than-predictable art form, according to the environment department. The drought has stretched into its second year in most provinces. Less raindrops have splashed on to the ground than at any point in the last century.
Relief should come in the form of La Niña – El Niño’s sometimes benevolent sister. This cools the Pacific Ocean and brings rainfall to the southern hemisphere. Traces of this change are already being picked up by meteorologists. But its drought-abating rain has, historically, created the worst floods in Southern Africa.
It will also not stop 2016 from going down as the hottest year in recorded history.