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Extreme heat and dairy production

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Climate change is causing more frequent and intense heat waves in the United States. Studies show that not only are heat waves now occurring more often, but that the average heat wave season is nearly 50 days longer now than it was in the 1960s.  The overall rise in temperatures, linked to climate change, has led to increased health risks and fatalities from extreme heat. 

As humans face increasing health risks from this extreme heat, livestock are also suffering from the effects of rising temperatures.  Extreme heat negatively impacts dairy production by causing heat stress in cows, which can reduce milk yield, quality, and the cows’ overall health.

A new study by researchers from the University of Illinois Urbana-Champaign analyzed milk production data from 18,000 dairy farms across nine Midwest states between 2012 and 2016.  The researchers found that high heat and humidity have led to a 1% decline in annual milk yield. While this might not sound like a lot, it amounts to about 1.4 billion pounds of milk over five years from the 18,000 herds included in the study – equivalent to about $245 million in lost revenue.

The study, which was recently published in the journal Food Policy, found that small farms are hit harder than large farms.  Larger farms may be able to mitigate some of the effects through management strategies, such as open barn sides, fans, and sprinklers.

Using projections from 22 different climate models, the research team estimates that more frequent extreme heat will increase milk yield losses by about 30% by 2050. 

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Illinois study: Extreme heat impacts dairy production, small farms most vulnerable

Photo, posted March 13, 2018, courtesy of Gosdin via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Too hot for people

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The effort to mitigate the effects of climate change has a goal of keeping the global temperature increase below 1.5 degrees Celsius above preindustrial levels.  To date, the average global temperature has increased by more than 1 degree.  We hear about rising sea levels, powerful storms, and various other alterations in climate and weather patterns.  A new interdisciplinary study by three institutions looked at the impact of surpassing the 1.5-degree level upon people being able to withstand heat and humidity.

Humans can only withstand certain combinations of heat and humidity before their bodies begin to experience heat-related health problems such as heat stroke and heart attacks. 

In human history, temperatures and humidity that exceed human limits have been recorded only a limited number of times and only for a few hours at a time, in the Middle East and Southeast Asia.

According to the new study, if global temperatures increase by 2 degrees Celsius above preindustrial levels, the 2.2 billion residents of Pakistan and India’s Indus River Valley, the one billion people living in eastern China, and the 800 million residents of sub-Saharan Africa will annually experience many hours of heat surpassing human tolerance.

If the warming continues further to 3 degrees, heat and humidity levels that surpass human tolerance would affect the Eastern Seaboard and the middle of the US from Florida to New York and from Houston to Chicago.

The worst heat stress will occur in regions that are not wealthy and that are experiencing rapid population growth.  But even wealthy nations will not escape from the expansion of conditions that are too hot for people.

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Climate-driven extreme heat may make parts of Earth too hot for humans

Photo, posted June 28, 2018, courtesy of Ivan via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Europe Is Warming Very Quickly | Earth Wise

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According to a new report from the World Meteorological Organization, Europe is warming faster than any other inhabited continent.  The result of the rising temperatures has been increasingly severe heat waves, flood, and wildfires.

The Paris Climate Agreement has set a goal of limiting warming to no more than 2 degrees Celsius above pre-industrial levels and, if at all possible, to no more than 1.5 degrees.  To date, the planet has warmed by 1.2 degrees and, with greenhouse gas emissions continuing at record levels, the temperature keeps going up.

These numbers refer to the global average.  Some places have warmed more and others less.  The Arctic has been warming four times quicker than the rest of the world.  In terms of direct impact on large populations, Europe has already surpassed the 2-degree mark, having reached 2.3 degrees last year.  In 2022, many countries in western and southwestern Europe had their warmest year on record. Weather-related economic damages totaled $2 billion, mostly as a result of storms and floods.

Europe is trying to do its part in mitigating climate change by making major gains on clean energy.  Wind and solar generated 22% of Europe’s power in 2022, which is more than either natural gas or coal produced.  Europe is trying to do its share, but the warming climate is a global phenomenon and will require a global effort to mitigate its effects.

The record-breaking heat stress experienced by Europeans last year cannot be considered a one-off occurrence.  It is part of a pattern that will make weather extremes more frequent and more intense over time.

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The Fastest-Warming Continent, Europe Has Already Heated by More Than 2 Degrees C

Photo, posted September 26, 2011, courtesy of Ben Ramirez via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Training Corals To Tolerate Heat | Earth Wise

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When ocean water is too warm, corals expel the algae that lives in their tissues, which causes the coral to turn completely white.  This is called coral bleaching.   When this happens, the coral is not dead.  However, corals are dependent upon the symbiotic relationship with algae and if conditions don’t improve, they don’t let the algae back in and the corals will die.

According to the National Oceanic and Atmospheric Administration, between 2014 and 2017, around 75% of the world’s tropical coral reefs experienced heat stress severe enough to trigger bleaching.  For 30% of the world’s reefs, the heat stress was enough to kill the coral.

According to new research by the University of Miami published in the journal Coral Reefs, corals subjected to a stressful regimen of very warm water in the laboratory came to be more tolerant of high temperatures, offering a potential tool for preserving ailing coral reefs.

In the study, some corals were kept in water at a constant temperature of 82 degrees while others saw water temperatures fluctuating between 82 degrees and 88 degrees.  After 90 days of this treatment, the corals exposed to variable temperatures were able to tolerate high heat for longer periods before bleaching.  This training regime is akin to an athlete preparing for a race.

The findings suggest a possible approach for restoring coral reefs.  Nursery-raised corals that are “trained” to tolerate heat could be planted onto reefs endangered by warming waters.  Reefs populated by corals with boosted stamina to heat stress could have a greater chance of surviving the warming waters of the oceans.

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Some Corals Can Be Conditioned to Tolerate Heat, Study Finds

Photo, posted December 16, 2015, courtesy of Big Cypress National Preserve via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Helping Corals With Beneficial Bacteria | Earth Wise

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A group of researchers at the King Abdullah University of Science and Technology in Saudi Arabia is exploring a novel technology to improve the health of corals.  Around the globe, corals are being stressed by pathogens, toxins, and warming waters leading to widespread bleaching events.

The new idea is to introduce beneficial bacteria to the corals, thereby boosting the strength and resilience of their symbiotic partners.  The concept is akin to the use of probiotics in plant science.  Corals rely on bacterial and algal symbionts to provide nutrients, energy (through photosynthesis), toxin regulation, and protection against pathogens.  

The researchers selected bacteria that are naturally symbiotic to specific coral species on reefs in the Red Sea, ensuring that no alien bacteria are accidentally introduced.  A probiotic cocktail comprising six bacteria strains was used in a laboratory setting.  Results in the lab have been promising so far, as they have observed dynamic and metabolic alterations to the corals that boosted their chances of survival under heat stress. 

Success in the lab will need to be translated to success in the open oceans, which is challenging.  Scaling up and seeding whole reefs might involve robots and artificial intelligence in order to deliver probiotics either into sediments or directly onto corals.

The use of beneficial microorganisms is not the solution to the global destruction of coral reefs.  Only worldwide CO2 mitigation can ultimately accomplish that.  But the probiotic approach might buy corals some time as they deal with shifting environmental pressures and try to adapt to a changing world.

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Microbiome boost may help corals resist bleaching

Photo, posted March 18, 2018, courtesy of Steven dos Remedios via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Helping Out Corals With Cool Water | Earth Wise

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Coral bleaching is happening five times more frequently than it did forty years ago.  Its increasing occurrence is a result of global warming which leads to marine heat waves – periods of higher ocean water temperatures.  Heat stress on living coral animals causes them to expel the algae that live symbiotically within the coral structure.  As the algae is expelled, the coral fades in color looking like it is bleached.  Without its algae partner, the coral eventually dies.

Given the increasing occurrence of marine heat waves, scientists are seeking novel ways to decrease heat stress in corals.  A new study by the Bermuda Institute of Ocean Science is investigating the use of artificial upwelling – the application of cooler, deep water – as a way to mitigate thermal stress on corals.

Upwelling is a natural process in the ocean in which winds push surface water away from a region – for example, a coastline – which then allows the uplift of deeper, colder waters to the surface.  Because such deeper waters are typically rich in nutrients, upwelling is important for supporting many of the world’s important commercial fisheries.  For this reason, artificial upwelling has sometimes been used to increase fish stocks in certain locations.

The new work placed coral colonies in aquaria in Bermuda and tested the effects of varying amounts and temperatures of deep cold-water pulses upon corals subjected to thermal stress.  The results showed that even short intrusions of cooler deep water (less than two hours per day) can mitigate thermal stress in corals.  The next steps are to find suitable parameters for artificial upwelling that maximize the benefits while minimizing potential harmful side effects on the corals and the ecosystems they support.

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Can pumping up cold water from deep within the ocean halt coral bleaching?

Photo, posted February 24, 2008, courtesy of Roderick Eime via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

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