Weather extremes from around the world fueled by climate change in 2013
Monday, October 6, 2014, 2:11 PM - With our warming world setting us up for new levels of extreme weather, isolating its influence in the weather we are seeing now hasn't been easy. However, a new report shows that after carefully studying 16 different incidences of extreme weather in 2013, scientists have found that over half showed an influence from climate change. Here they are, broken down into six main events:
1. New Zealand's worst drought in over 40 years
In the early months of 2013, when the southern hemisphere was in the middle of summer, New Zealand's North Island was suffering through a widespread, major drought. Costing the country over $1 billion in agricultural loses and with affects that are expected to stretch into 2015, it was the worst drought the region has experienced in 41 years of record-keeping.
According to scientists from the Victoria University of Wellington and New Zealand's National Institute of Water and Atmospheric Research: "For the 2013 New Zealand drought, evidence from a number of models suggests that the meteorological drivers were more favorable for drought as a result of anthropogenic climate change."
2. Australia's 'Big Dry' turns into a record-breaking year for heat
(Image credit: climatecouncil.org)
After nine years of extremely dry conditions, which Australians called 'The Big Dry', ended around mid-2012, the next year after that turned into its hottest on record. As the graphic above shows, Australians suffered through a record-breaking summer during the early months of 2013, but it was the period of May through August - from mid-fall through late-winter in the southern hemisphere - that pushed the year to be the hottest ever seen there, since record-keeping began back in 1910.
Five separate studies in the report, penned by over a dozen leading climate scientists, unanimously point to anthropogenic climate change as at least partly responsible for this year of extremes.
In two of these studies, researchers from the Australian Research Council Centre of Excellence for Climate System Science stated: "Human activity has increased the risk of experiencing the hot Australian summer of 2012/13, as measured by simulated heat wave frequency and intensity, by two- and three-fold, respectively," and "anthropogenic climate change has caused a very large increase in the likelihood of extreme events such as the record Australia-wide average temperatures in September, spring, and the 2013 calendar year."
3. Extreme rains and flooding in Northern India
In June of 2013, northern India received the greatest amount of rainfall on record, dating back to 1951. The subsequent flooding from this event left over 100,000 people homeless and it claimed over 5,000 lives.
According to a study of the event, from June 14 to 17, the region affected by this extreme rainfall "received four-day total precipitation that was unprecedented in the observed record," and the heaviest rainfall, on June 16, was more than double the previous June record rainfall amount in that 62 year period. The team of researchers, from the Woods Institute for the Environment, Oak Ridge National Laboratory and Scripps Institution of Oceanography stated: "Cumulative precipitation in northern India in June 2013 was a century-scale event, and evidence for increased probability in the present climate compared to the preindustrial climate is equivocal."
NEXT PAGE: More climate connections and the extreme events in 2013 that happened all on their own
4. Extreme heat in Southeast Asia
In the summer of 2013, temperatures soared across Eastern China, Japan and South Korea, to some of the highest values on record, especially in the months of July and August.
Based on studies done by scientists from all three countries, the report states: "Long duration heat waves during the summer and prevailing warmth for annual conditions are becoming increasingly likely due to a warming planet, as much as 10 times more likely due to the current cumulative effects of human-induced climate change, as found for the Korean heat wave of summer 2013."
5. A year of precipitation extremes across the United States
While the western U.S. has been suffering under an extreme dry spell, other parts of the country experienced record-setting rain and snowfall events in 2013.
Studies have found that events like the heavy rainfall and flooding seeing in Colorado in early September, and the early-Autumn blizzard in South Dakota in October, are actually expected to be less likely to happen with climate change. The report also states that extreme precipitation events during 2013 were influenced less by climate change than the extreme temperature events were. However, when looking at U.S. seasonal precipitation amounts for the year, researchers with NOAA - the National Atmospheric and Oceanic Administration - found "some suggestion of increased risk attributable to anthropogenic forcing" for extreme precipitation events, although they were cautious about emphasizing this, since the long-term trends were less clear. Mainly, they attribute events in the upper Midwest, through parts of the Northern Tier (boarding with Canada) and in the US Northeast, at least partially, to this anthropogenic forcing.
6. California's extreme drought
There's some indication from studies that the effects of climate change on the western U.S., especially when it comes to unusually warm sea surface temperatures, would tend to even out the risks of extreme drought. However, researchers have shown that a large-scale high pressure cell over the northeastern Pacific Ocean, nicknamed a 'ridiculously resilient ridge', has been responsible for diverting Pacific storms - which California depends on for its annual rainfall and snowfall totals - north into Alaska and northern British Columbia instead. Researchers with Stanford University found that these 'ridiculously resilient ridges' have been happening more often now than they did in preindustrial times.
It's not all about climate change
Although it may seem like every extreme weather event is immediately blamed on climate change, it's not always so. Scientists examine these events very carefully to see if there's a discernible 'signal' from the expected effects of global warming and climate change, and not all make the cut.
Of the 16 extreme weather events that were examined in this report, nine were attributed, at least in part, to the effects of climate change. That leaves seven of the events where climate change was found to either have an uncertain or no net effect, or it was found that climate change would actually make those kinds of events less likely to happen. Thus, according to current research, these events tended to happened due to natural variability in the weather.
The full report, with each research paper used in the study, can be found on the NOAA website (click here). The full Bulletin of the American Meteorological Society State of Climate in 2013 report can be found on the AMS website (click here).