Polar vortex puts world into deep freeze
Will there be another ice age? Many believe the answer is yes – but scientists say that global warming caused by human activity may have delayed it by over 50,000 years.
The north wind howls and the mercury plummets. An arctic winter is sweeping across Europe and North America, bringing sub-zero temperatures to every state in the US and blizzards to the east of England. The heat waves of last summer are a distant memory.
But this bitter weather really started a month ago as dramatically warming air, high up in the arctic atmosphere. This high-altitude polar vortex normally keeps a lid on the frozen weather at the north pole. But when it warms, the wind weakens and changes direction, pushing cold air southward.
This is called sudden stratospheric warming and is a fairly common weather pattern, occurring on average six times every decade. In 2018, it created a hurricane-strength storm dubbed the beast from the east. In 2019, Lake Michigan froze and temperatures in Minnesota dropped to -48°C, colder than the south pole.
But there is more to our extreme weather than the polar vortex. The Earth’s climate is affected by many cycles, some changing slowly over millennia, others more quickly. Every 11 years, the sun’s activity drops to a low called the solar minimum, leading to colder winters. And our star has just entered the quietest period in a century.
Occasionally, these minimums can last decades. Between 1672 and 1699 fewer than 50 sunspots were recorded, compared to over 40,000 in modern times. This was the Maunder Minimum and it happened at the same time as exceptionally cold weather known as the Little Ice Age. Historians link its harsh winters and failed harvests with major events from the Thirty Years’ War to the collapse of the Chinese Ming Dynasty.
However, geologists say the Little Ice Age is a misnomer. There have only been five major ice ages in the Earth’s 4.5 billion year history. The last one, the Quaternary Period, began three million years ago – and we are still in it. Over this stretch of geological time, the glaciers have expanded and retreated as the climate has repeatedly cooled and warmed. The last glacial period ended 11,700 years ago, and it is this that is known as the last ice age.
Since then, Earth has enjoyed a milder climate. And humanity has taken advantage of the fine weather, discovering agriculture around 10,000 years ago and building civilisation as we know it. But these interglacial periods can’t last forever. The Earth is due another ice age.
Except there is no sign of one anytime soon. Glaciers are shrinking instead of growing. Twenty-eight trillion tons of ice has melted since 1994. And the world is not cooling. It is heating up by over 1.5°C per century, faster than at any point in the last two thousand years.
Scientists warn that global warming caused by human activity may have delayed the next ice age by over 50,000 years. Others suggest we have stopped the glacial cycles altogether. This would mark a new period in the Earth’s history, the Anthropocene, in which humans and not glaciers are the biggest factor determining our weather and climate.
Will there be another ice age?
The big freeze
Some say yes, it is just a matter of time. Humans are fixated on dramatic changes in weather, but the ice ages are about gradual shifts in climate over thousands of years. Sunspots, volcanic activity, the polar ice caps and the earth’s orbit all contribute to the complex cycle of rising and falling temperatures. At some point in the future, ice sheets will again extend across the globe.
Others say no, we have changed the planet’s climate too much. In the short term, the warming arctic will lead to more cold winters further south. But the bigger picture is of runaway climate change. Throughout the history of its existence, the Earth has cycled through ice ages and greenhouse periods – when the atmosphere was too warm for ice to form. Now, we are in danger of creating a greenhouse planet that cannot be reversed.
- Would an ice age be good for the planet?
- Will our grandchildren see snow?
- Design a house to survive an ice age winter of -30°C degrees celsius, massive snowdrifts and freezing winds.
- Use the Expert Links to create a timeline that shows the last glacial period, the Little Ice Age and the solar maxima and minima.
Some People Say...
“There’s an east wind coming all the same, such a wind as never blew on England yet.”Arthur Conan Doyle (1859 – 1930), British writer
What do you think?
Q & A
- What do we know?
- It is generally agreed that two main factors affect global temperature: solar radiation and greenhouse gasses. The Serbian astronomer Milutin Milankovitch showed how the tilt, wobble and orbit of the Earth influence the cycles of glacial and interglacial periods. According to his observation, the Earth should be cooling. However, the carbon dioxide in the atmosphere is causing a warming effect that is more powerful than the cooling caused by reduced solar radiation.
- What do we not know?
- One main area of debate is around the Little Ice Age. Contemporaries blamed the foul weather on sin and witchcraft, but historians believe a combination of the solar minimum and increased volcanic activity caused climate cooling. Between 1630 and 1850 ash clouds from 16 major eruptions blocked out solar radiation. Another theory links the Little Ice Age to the depopulation of the Americas during European colonisation. Other scientists call the ice age a myth based on anecdotal evidence.
- Mercury plummets
- Mercury is the only metal that is liquid at room temperature and is used in thermometers. It expands with increased heat, and contracts in colder temperatures. So, when the temperature drops, so does the mercury.
- Polar vortex
- Thirty miles above the Earth in the stratosphere, these winds can blow up to 155mph, the strength of a category five hurricane.
- Beast from the east
- The snowstorm’s meteorological name was Anticyclone Hartmut. It collided with the Storm Emma on 2 March 2018, causing significant snowfall in the UK and Ireland.
- Solar minimum
- Activity is measured in sun sports and sun flares. A solar maximum can cause power outages and damage to satellites and communication systems.
- Thirty Years’ War
- Failed harvests and higher taxes led to unrest across Europe and indirectly contributed to one of the deadliest wars in history.
- Ming Dynasty
- In 17th-Century China, unusually cold and dry weather led to famine and revolts against the ruling dynasty. Invaders from the north took advantage and overthrew the Ming, establishing the Qing Dynasty.
- The Little Ice Age was extremely short (a few hundred years) compared to geological ice ages that last millions of years and glacial periods that impact the global climate.
- Greenhouse gasses may have begun to rise 8,000 years ago as farming practices expanded, warming the atmosphere and delaying the next glacial period.
- The concept of a new geological epoch is controversial and contested. One theory is the Anthropocene began around 1610 following the colonisation of the Americas. Another proposes the new epoch began in 1950 with rising global temperatures and accelerating human activity.