Study by weather experts reveal that time spans experiencing global warming and cooling is only a regional phenomenon. It did not strike all parts of the world together. Writers contributing to novel studies in Nature and Nature Geosciences took help of the proof left on nature by climatic modifications. Tree rings and coral reefs, for example, were affected by extreme weather changes over the past 2000 years. They bore visible marks on them as a confirmation of abrupt climate change.
Reports on geological study and the impact of rising temperature on the surface of the earth, giving birth to Little Ice Age and mediaeval warm periods, lead to new findings. They suggest that events were more focused on a particular area on the Earth. It did not have a global reach at the same time – but is the Earth facing an abrupt climate change since the past few years?
How abrupt climate change happened globally?
The regional piecemeal geological and climate variations as a consequence of temperature change were unified into a single global abrupt climate change. And this has transpired only very recently. According to a research carried out jointly by Nathan Steiger and his colleagues at Lamont Doherty Earth Observatory of Columbia University, true global warming is a 20thcentury phenomenon.
The intensity and rise in temperature with respect to time elapsed was far more rapid in the second half of the 20th century. The rate of temperature rise far outmatches what was experienced by similar periods during past 2000 years. Previous studies on climate change have pin-pointed eras from past 2000 years that have faced abrupt climate change.
These eras have been identified as:
- Little Ice Age (800 to 1200 years)
- The Dark Ages Cold period (400 to 800 years )
- The Roman Warm period (stretching over first few centuries AD)
Even during Little Ice Age, the coldest part was a consequence of its position on earth. In the past 2000 years, the coldest temperatures were recorded in the 15th century and its location was in the Pacific Ocean. In the 17th century, it was concentrated in the North Western Europe and South East part of North America.
Other parts of the world had to wait till the middle of 19th century to experience this abrupt climate change, where temperature dropped to its record low. As a contrast, figuring out the warmest period in the past 2000 years doesn’t involve much procedural complications. In 98% of the total global atmosphere affected, the warmest temperature in the past 2000 years was encountered in the late 20th century.
Although not a part of this research team, Kevin Anchukaitis, a paleontologist supports the claim that different parts of the globe had their warmest and coldest phases at different points of time. It did not happen all at the same time.
Causes of abrupt climate change and extreme weather:
In a study led by Neukon supported by his team, it was reported that volcanic eruptions caused the rising of temperature. The span of this temperature rise extended well over two to three decades. The sun’s radiation in comparison did not have pretty much of a notable impact. Another study conducted by Stefan Bronnimann and team reported it was five shuddering volcanic eruptions that were responsible for abrupt climate change.
The Tamborra eruption in 1815 had a major role in deciding the climate at the close of the Little Ice Age. Chain effects of volcanic throw-ups were subsequent cooling down of atmosphere, no rains in Africa followed by drought and change in storm routes over Europe. Consequently, the Alps received heavy snowfall and glacial build-up.
This recent period of high volcanic activity was not encountered in the past 2000 years. It finally overlaps with the beginning of the era of industrialization. It is thought-provoking to find out the actual cause of global warming over last 2000 years. Were there multiple factors contributing to – it including greenhouse emissions from rapid industrialization?
Reduction of milder days in different places of the earth:
Simply because of greenhouse gas emissions generated by human activities, 10 – 13 % of milder days would be lost, concludes a study report. For days to come, weather experts forecast that mild weather losses would happen in tropical regions owing to mounting heat – humidity combination. Africa, Asia and South America would be the worst hit continents.
By the close of this century, some of these continents would experience 15 to 50 lesser milder days. Research conducted by NOAA and Partners infers that this abrupt climate change would lead to economic harm. Prolonged heat waves will adversely affect public health.
Places on the earth to see milder days:
Not everything is bad about abrupt climate change. Parts of the Northern Hemisphere like in US, Canada and Northern Europe currently in the grip of severe cold would gain milder days. These specified regions along with other mountainous areas in Northern Hemisphere will gain 10 to 15 milder days on an average at the end of 21st century.
Abrupt climate change and its effect on India:
Global warming is a threatening trend and India is no exception from suffering its fallouts. Long span of drought ends in a sudden rush of heavy downpour, causing flooding. The current year had seen a meager rainfall during monsoon and yet states of North East India had been under flood waters consequent upon a deluge of heavy rainfall.
This has been a warning signal since last few years that there is something very wrong with the climate change. A study carried out by Indian Institute of Technology, Gandhinagar, had forecasted that incidence of sudden rainfall after a prolonged drought is an outcome of climate change. Climate change has its roots in global warming!
Modern technology to simulate global climate change:
Computers have been used for past 40 years to extrapolate a stable picture of climate change. Greenhouse emissions like carbon dioxide and methane liberated from human activities have been fast contributing to global temperature rise. Previous computer models have shown a twice increase of CO2 content from pre-industrial levels have led to a temperature rise by 2 degrees Celsius to 4.5 degrees Celsius, after which a temperature equilibrium is reached.
But the rise hasn’t halted after attaining a transient state of temperature balance. Atmospheric carbon dioxide at 408 parts per million at the current level is on the rise. This is a menacing trend pointing to a disturbing fact within next few decades global temperature would shoot up by 2 degrees Celsius. It will stabilize there before taking another leap.
Thawing of Arctic icecap:
In the past month, the average depth of Arctic ice has dropped to an all time low. Last January, ice in Antarctic sea had also hit a record low from which it had made a slight improvement. In a satellite image, Arctic sea winter maximum and Antarctic sea summer minimum in 2019 revealed their seventh smallest status in terms of thickness. A gradual fall in thickness of Arctic ice since 1970 with dark color on surface and lighter color at the bottom is an alarming phenomenon. It is an indication of catastrophic results of global warming from which our Earth is not very far away.
Global surface temperature in 2019 is to be either the second or third warmest since mid-1800s:
The trend of extreme temperature situation is likely to exist this year buoyed by a moderate El Nino effect. Ocean Heat Content has touched a new record this year. Current data reveals the rise of ocean levels by nearly 8.5 cm than recorded in early 1990s.
Several International Groups recording and reporting Global Surface Temperature predicts 2019 is likely to the second or third warmest year on record. With the temperature data available for only the first quarter of this year, the probability of being the warmest year on record cannot be ruled out. Unless we restrict carbon dioxide and methane emission within next 10 years, extreme weather conditions followed by drastic climatic change would be a usual phenomenon.