global temperatures

Climate Change And El Niño

December 2, 2019 By EarthWise Leave a Comment

The term El Niño refers to a large-scale ocean-atmosphere climate interaction linked to a periodic warming in sea surface temperature across the central and east-central equatorial Pacific Ocean. Amazingly, the phenomenon was originally recognized by fishermen off the coast of South America in the 1600s, with the appearance of unusually warm water in the Pacific Ocean.

According to a new study published in the Proceedings of the National Academy of Sciences, climate change is increasing the frequency of extreme El Niño events, leading to intensifying droughts, worsening floods, and shifting hurricane patterns.

The study, led by scientists in China and the US, looked at data from 33 El Niños dating back to 1901. Since the 1970s, El Niños have been forming farther to the west in the Pacific Ocean, where temperatures are warmer. Strong El Niños can cause severe drought in dry climates such as Australia and India, intense flooding in wetter climates such as the US Pacific Northwest and Peru, and more hurricanes to form in the Pacific and fewer in the Atlantic.

Before 1978, 12 out of 14 El Niños formed east of the International Dateline. Since 1978, all 11 have formed in the central or western Pacific Ocean a shift of hundreds of miles. There have been three so-called super El Niños since the shift – in 1982, 1997, and 2015. These have set new average temperature records and triggered catastrophic natural disasters.

With rising global temperatures, El Niños are likely to continue to intensify, with major impacts on human societies around the world.

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Climate Change is Making El Niños More Intense, Study Finds

Photo, posted January 20, 2016, courtesy of Los Angeles District via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Hundred-Year Floods Becoming One-Year Floods

September 26, 2019 By EarthWise Leave a Comment

By definition, 100-year floods are intense flooding events that historically tend to happen once every 100 years. Put another way, a 100-year flood has a 1 percent chance of happening in any given year.

According to new research published in the journal Nature Communications, rising global temperatures may turn 100-year floods into annual occurrences in parts of the United States. The increase in severe coastal flooding events by the end of this century will be a result of rising sea levels and stronger, more frequent tropical storms and hurricanes.

The study, led by researchers at Princeton University and MIT, examined flood risk for 171 counties along the US East Coast and the Gulf of Mexico. Their analysis concluded that 100-year floods will become annual events in New England. In the US Southeast and Gulf of Mexico, counties could experience such floods as often as every year up to as seldom as every 30 years.

Previously, most analysis of coastal flooding has looked only at the impact of sea level rise on flood risk. This new research combined the risk of rising seas with projected changes in coastal storms over the course of this century. Data from the Gulf of Mexico revealed that the effect of stronger storms is comparable with or even more significant than the effect of sea level change for 40% of the counties studied. So, neglecting the effects of storm climatology change is likely to significantly underestimate the impact of climate change in many places.

The hope is that more comprehensive flood risk data can be used to create more effective climate resiliency strategies all the way down to the county level.

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100-Year Floods Could Soon Happen Annually in Parts of U.S., Study Finds

Photo, posted August 31, 2017, courtesy of the U.S. Department of Agriculture via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The State Of The Climate

September 19, 2019 By EarthWise Leave a Comment

The federal government has issued the annual State of the Climate report and it is a sobering one. The report states that carbon dioxide in the atmosphere rose to levels the world has not seen in at least 800,000 years. Global carbon dioxide concentrations reached a record 407.4 parts per million during 2018. That is 2.4 ppm more than 2017.

Other greenhouse gases like methane and nitrous oxide also continued their rapid increase. Taken together, the global warming power of greenhouse gases was 43% stronger than it was in 1990.

Along with greenhouse gases, global sea levels also reached their highest levels on record for the seventh consecutive year. Ocean levels are rising about an inch per decade, but that number may rise if ice melt at the poles continues to accelerate.

Global temperatures had their fourth highest level on record in 2018, slightly lagging 2016, 2015, and 2017 for the highest ever. A La Niña over the Pacific cooled ocean waters for part of 2018, keeping temperatures a bit lower. So far, 2019 is on track to be the warmest year in recorded history.

Global sea temperatures also set a record level in 2018. And glaciers continued to melt at an alarming rate for the 30th consecutive year.

The State of the Climate report is yet another in a series of expert, science-based reports that continue to sound the alarm about the climate crisis. Climate change is affecting our weather, agricultural productivity, water supply, public health and national security. Unfortunately, the facts continue to be drowned out for many people by blogs, pundits, and posts on social media.

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Greenhouse Gases Reach Unprecedented Level

Photo, posted January 13, 2014, courtesy of Ronnie Robertson via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Shifting Ecosystems

August 29, 2019 By EarthWise Leave a Comment

The Great Plains ecosystem has been shifting northward over the past fifty years, driven by climate change, wildfire suppression, energy development, land use changes, and urbanization. The ecosystem is an area historically rich with grasslands and shrub steppe and is prime habitat for grassland birds.

According to a recent study published in the journal Nature Climate Change, the northernmost ecosystem boundary of the Great Plains has moved more than 365 miles north since 1970, amounting to about 8 miles a year. The region’s southernmost ecosystem boundary has shifted 160 miles north, or about 4 miles a year.

The study used bird distribution data as an indicator of shifting ecosystem boundaries. The researchers analyzed 46 years of data for 400 bird species across a 250-mile-wide strip stretching from Texas to North Dakota. They tracked how the birds’ distributions changed as a measure of how these ecosystems were shifting.

While climate change has been a major driver of these ecosystem shifts since the 1970s, several other factors such as wildfire trends, land use changes, and invasion of tree species into grassland habitat have also played a role. Like most things in ecological systems, the changes are likely to have multiple causes. One cannot really separate causes like tree invasions, warming climate, and wildfires, as they are all interrelated.

Using bird distribution patterns for tracking ecosystem shifts could be a useful tool for scientists and land managers in the coming decades to give them an early warning of how habitats are changing in response to rising global temperatures and therefore allow them to take action to protect vulnerable species.

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Great Plains’ Ecosystems Have Shifted 365 Miles Northward Since 1970

Photo, posted March 24, 2017, courtesy of Rick Bohn / USFWS via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.