LONDON: The Arctic Ocean could experience ice-free summers within the next 20 years — much earlier than previously predicted — unless human greenhouse gas emissions are greatly reduced, a study warns.
Computer models predict climate change will cause the Arctic to be nearly free of sea ice during the summer by the middle of this century, due to a natural, long-term warming phase in the tropical Pacific, in addition to the human-caused warming.
However, a closer examination of long-term temperature cycles in the tropical Pacific points towards an ice-free Arctic in September, the month with the least sea ice, on the earlier side of forecasts, according to the research published in the AGU journal Geophysical Research Letters.
“The trajectory is towards becoming ice-free in the summer but there is uncertainty as to when that’s going to occur,” said James Screen, an associate professor at the University of Exeter in the UK.
There are different climate models used by researchers to predict when the first ice-free Arctic September will occur.
Most models project there will fewer than one million square kilometers of sea ice around the middle of this century, but projections of when that will occur vary within 20-year windows due to natural climate fluctuations.
The climate model used in the new study predicts an ice-free Arctic summer sometime between 2030 and 2050, if greenhouse gases continue to rise.
By accounting for a long-term warming phase in the tropical Pacific, the new research shows an ice-free Arctic is more likely to occur on the earlier side of that window, closer to 2030 than 2050.
Ocean temperatures in the Pacific always vary from month-to-month and from year-to-year, but slowly evolving ocean processes cause long-term temperature shifts lasting between 10 and 30 years.
These shifts in temperature, known as the Interdecadal Pacific Oscillation (IPO), translate into an approximately 0.5 degree Celsius shift in ocean surface temperature in the tropics over the 10- to 30-year cycle.
Around five years ago, the Pacific began to switch from the cold to warm phase of the IPO. Screen and his co-author plotted predictions of when an ice-free Arctic would occur in model experiments where the IPO was shifting in the same direction as the real world.
They compared these to predictions where the IPO was moving in the opposite direction, that is, switching from a warm to cold phase.
They found model predictions that were in sync with actual conditions showed an earlier ice-free Arctic, by seven years on average, than those predictions that were out of step with reality.
Screen says these results need to be interpreted as part of a bigger picture. Human-caused climate change is the main reason for sea ice loss, so the timing of the first ice-free summer will also depend considerably on whether greenhouse gas emissions continue to rise or are curtailed.
However, the new results do suggest that we are more likely to see an ice-free September on the earlier side of the 20-year window of predictions. (AGENCIES)
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SPO-IND-LD RAHUL
Controversy has humbled me and I value
India cap even more: KL Rahul
BENGALURU, Feb 28:
The “hard time” that he endured in the wake of a chat show controversy has “humbled” K L Rahul and the Indian batsman says he now values his national cap more than ever.
Both Rahul and Hardik Pandya were provisionally suspended for their loose comments on women during a popular chat show. Their bans were later revoked pending an inquiry.
The off-field controversy erupted after Rahul endured a dismal run in the four-Test series in Australia but he is back in the national team after finding his feet with the India A side.
“It was a hard time no doubt. I mean, as a player, as a person, everyone has to go through difficult times and it was my time to go through that and I like I said it gave me time to reflect on my game, on myself. I have always been someone who takes things as it comes,” said Rahul after the second T20 International.
India lost the short series 0-2 but Rahul made a successful comeback with scores of 47 and 50. After he was sent back from Australia, Rahul was given the opportunity to regain form in the India A home series against England Lions and he made it count.
Asked if the entire controversy has changed him as a person, the 26-year-old said:”It has humbled me a little bit and you know. I respect the opportunity that I have gotten to play for the country. The dream of every kid is to play for the country and I am no different.
“Just to value where I am, just to keep making opportunities count and put my head down and keep working on my cricket,” said the man from Karnataka.
Rahul said the India A stint under coach Rahul Dravid helped him immensely.
“I got some time off from international cricket, so I could come back to India and reflect on what was not going right for me. Fortunately, I got to play some India A games where the pressure is a bit less and where I could focus on my skill and my technique,” said Rahul.
“I got to spend a lot of time with Rahul Dravid, working on my game and chatting about cricket. He helped a lot in the five games I played for India A. The time I have spent in the middle has helped. It is nice to be back with the boys and back in blue,” the relief was palpable as he spoke.
Rahul hopes that it is a blessing in disguise that he courted controversy early in his international career.
“I hope so. Things happen like I said. Four-five years with Team India . Learnt about the game, where I stand as a cricketer, as a person so just try to get better from there and be consistent and keep performing.”
Rahul admitted that he felt the pressure after making a comeback into the Indian team.
“There was little bit of pressure as I have been away from team. But I came into the series with a little bit of runs, so yeah happy to be back.”
India were not able to defend 190 for four on Wednesday and ended up being outplayed in the series. Local hero Rahul said chasing at Chinnaswamy in the night becomes easier with dew factor playing out.
“In the second innings, dew always has an effect. We have seen that in Chinnaswamy. If you see the stadium’s history, chasing has been easier. But can’t take credit from Glenn Maxwell.
“He (Maxwell) played a very good innings. Our bowlers tried their best but with a wet ball, it was always hard,” said Rahul, adding that India will have to find a way to contain Maxwell in the five-match ODI series starting on March 2. (AGENCIES)
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