My colleagues and I support these warming trends is rare as a result of the natural variability of the climate alone. The human-made effects of climate change appear to have worked in tandem with the important influence of natural variability in the eastern tropics on the Antarctic climate. Together, they represent the South Pole, the warming of one of the strongest global warming trends.
The South Pole is not immune to global warming
The south pole is in the coldest region of the Earth: the Antarctic plateau. Average temperatures range from -60 ℃ in winter to just -20 ℃ in summer.
The Antarctic is the general climate with a huge range of temperatures over the course of a year, with strong regional contrasts. Most of Western Antarctica and the Antarctic Peninsula were warming during the late 20th century. But the South Pole – in the distance and at high altitudes inside the continent cooled until the 1980s.
Scientists have been tracking the temperature at the Amundsen-Scott south pole Station, the most southerly Earth observatory, since 1957. It is one of the longest running full records temperature on the Antarctic continent.
Our analysis of the weather data from the South Pole station, shows that it increased by 1.8 ° c between 1989 and 2018, changing more rapidly since the early 2000s. During the same period, warming climate in West Antarctica suddenly stopped and the Antarctic Peninsula began cooling.
One of the reasons for the South Pole, warming was stronger at low pressure and stormy weather systems is from the Antarctic Peninsula, in the Weddell Sea. With the clockwise flow around the low pressure systems, this was the transport of hot and humid air over the Antarctic plateau.
South Pole global warming linked to the tropics
Our study also shows the ocean in the western tropical Pacific started warming rapidly at the same time as the South Pole. We have found almost 20% from year to year, temperature variations at the South Pole have been linked to ocean temperature in the tropical Pacific, and several of the warmest years at the South Pole over the past past two decades has passed when the western tropical pacific ocean has also been exceptionally hot.
To study this mechanism, we carried out a climate experiment model and observed this warming of the ocean produced in the atmosphere of the waveform which extends across the South Pacific, the Antarctic. This results in lower pressure in the Weddell Sea.
We know from previous studies that large regional variations in temperature change are partly due to the Antarctic shape.
The East Antarctic Ice Sheet, bordered by the South Atlantic and the Indian Ocean, extends further north than the West Antarctic Ice Sheet in the South Pacific. This results in two distinctly different weather conditions with different climatic impacts.
More stable, westerly winds to eastern Antarctica keep the local climate relatively stable, while frequent high intensity storms in high latitudes South Pacific transport hot and humid air from parts of the ‘West Antarctica.
Scientists have suggested these two types of weather, and the mechanisms behind their variability, are probably the reason for the high regional variability in Antarctica temperature trends.
What it means for the South Pole
Our analysis reveals extreme variations in the south pole, the temperature can be explained in part by natural tropical variability.
To estimate the influence of human-induced climate change, we analyzed more than 200 simulations of climate models observed in greenhouse gas concentrations during the period between 1989 and 2018. These climate models show the recent increases of greenhouse gases possibly contributed around 1 ° c of the total 1.8 ° c of global warming at the south pole.
We also used the models to compare the recent 30-year warming rates of the South Pole in temperature trends that could occur naturally, without human influence. The warming observed exceeds 99.9% of all trends, without human influence – and this means that recent warming is extremely unlikely under natural conditions, but not impossible. It seems that the effects of tropical variability have worked in concert with the increase in greenhouse gases, and the end result is one of the strongest global warming trends.
These simulations of climate models reveal the remarkable nature of the South Pole, the temperature variations. The observed south pole of temperature, with measurements dating from 1957, shows 30 years of temperature changes ranging from more than 1 ° c of cooling during the 20th century to more than 1.8 ° c of warming during of the past 30 years.
This means multi-decadal temperature oscillations are three times more than the estimated amount of human-caused global warming from climate change in the range of 1 ℃.
The variability of the temperature at the South Pole is so extreme that currently the masks caused by humans, the effects. Inland Antarctica is one of the few places on Earth where humans are responsible for warming cannot be determined with precision, which means that it is difficult to say whether or for how long. , the warming will continue.
But our study reveals extreme and sudden climate change is part of the climate of the interior of Antarctica. These will likely continue in the future, the human hiding work induced by global warming or the natural intensifying of human warming processes and the greenhouse effect working in tandem.
- Kyle Clem is a climate science researcher, Te Herenga Waka, Victoria University of Wellington