Climate change threatens future stability of rice ecosystems

New research claims climate and land-use change will greatly lower rice yields by the end of the century.

Rice yields in the Philippines and Vietnam could decline 30% by the year 2100.

“Because of a temperature increase in the Philippines and Vietnam of up to 4°C, rice yields can be kept steady only at the expense of natural vegetation, which would likely reduce native habitat and biodiversity,” say the authors of the new study published in the journal Environmental Research Letters.

The researchers created simulation models (from 2000-2099) comprising seven study areas to arrive at these conclusions. For climate change, two future scenarios were considered: a 1.5°C-2°C trajectory and a 3°C-4°C trajectory. For land use change, three future scenarios were chosen: low rice conversion, high rice conversion, and one based on global economic trends. The scientists then determined how these models affected ecosystem services—benefits humans gain from the environment—provided by rice ecosystems.

Along with rice yields, the study predicted a climate-induced decline in two other ecosystem services: carbon storage and carbon sequestration.

Carbon storage, a plant’s ability to store carbon long-term, is estimated to decrease 15% by the end of the century. This loss of storage capacity is caused by less photosynthesis (absorbing carbon) and more respiration (releasing carbon). Just like the proteins in our bodies, proteins driving photosynthesis slow down at high temperatures.

Land-use change also worsened carbon storage. As land is converted to rice fields, forests are decimated and the stored carbon is released

The outcome of climate and land-use change on carbon sequestration is more nuanced, though. Sequestration can be thought of as a carbon scale: photosynthesis as a weight on one side and respiration as a weight on the other side. Overall, by the end of the century, respiration outweighed photosynthesis—carbon sequestration declined by 12%.

However, when land-use change was added in high amounts, carbon sequestration shot up. To rapidly grow, crop plants—like rice—imbibe large amounts of carbon, while releasing little. This is in contrast to older forests, which absorb less carbon as their growth slows.

Another ecosystem service, irrigation water, was projected to increase by 10%-20%. Despite this, rice yields still markedly decreased. Although more land-use somewhat offsets the effects of climate change on yields in the early 21st century, those offsets are later negated in the latter half of the century by rising temperatures.

As rice is a staple food for 3.5 billion people—nearly half of the world’s population—declining yields could have prodigious consequences. Rice cultivation is the main source of income for over 100 million households across the world.

Cultural identity is at stake, too. These ecosystems shape farmers’ values, spiritual experiences, and connection to the natural environment.

“Locally specific land use policies and development plans have to consider more than the availability of rice,” the researchers say. “Cultural services to maintain future human wellbeing must be included.”

Flood

pexels-photo-709542.jpegThe opaque water rushed under the door, saturating the beige carpet. The winds whistled like a siren. Vee jumped to her feet. The storms had taken everything from her, and now it demanded more.

Vee wondered if things could have been different. If only we had listened to the Earth’s admonitions. If only we had not been so complacent. That was the folly of humans, she thought. We believe we are the progenitors of the universe. But this was not the case on that day—or any day. This wasn’t the time to think, though.

Vee’s body became automated. She had become accustomed to this routine—almost like doing dishes or brushing teeth.  Slow the flow of water, gather personal belongings, and run.

She leapt out of the window and onto the inundated lawn. That was her third “home” this month. Since federal aid to climate refugees was stymied, people began moving out of state to seek stability elsewhere. Dilapidated houses were abandoned like aged smartphones.

This year’s hurricane season had been exceptionally destructive. One right after another. Scientists estimate over 100 trillion gallons of rain has been dumped on the state so far.

A Category 5 freight train was approaching her. 63rd Street, Vee thought. The old red and white basketball stadium—reinforced walls, a titanium roof—would be her safest option.

It was a straight shot. A 45-minute walk at most. Vee rose to her feet and began sprinting. On the corner of Gilman and Hearst she began to hear a cacophony of shouts from a mauve and blue trimmed stucco house. Violent winds had forced a Live Oak through the terra-cotta roof. “We’re stuck!” “We’re stuck!” the voice screeched. “Please, help!” “Please!” another tiny voice pleaded.

If I stop, I’ll almost certainly be swept away by the floods, Vee thought. The murky waters were already accumulating. A thin layer had concealed the pavement below.

What would her daughter have said? Her daughter had only been six, and yet, she had emotional intelligence far beyond her years. Her daughter had watched coverage of the recent tsunamis in Southeast Asia—thousands were killed and millions were without electricity for months—and had sobbed for nearly two days.

“Mommy, we have to help those girls,” her daughter would have said. “They would do the same for us! What if it was us in that house?”

It was us, though, Vee thought. It was you. The waters had consumed you, swallowed you whole.

Her decision was predestined. Vee rushed toward the house and forced open the door. The fallen oak tree and other debris had created a dam—obstructing a portion of the hallway in which the girls were ensnared. Rain and turbid water pooled into the hallway. “Can you hear me?” Vee shouted. “I’m gonna try to dislodge this, but when I do, you have to get out immediately.”

The girls were crying. Their big brown eyes swelled with tears. “What do we do now?” The two asked anxiously.

“Move to the opposite side of the wall—away from the debris so nothing falls on you.” Vee replied.

Vee began plucking branches from the top of the debris, careful to avoid collapsing the structure. This reminded her of a game she once played with her nieces in San Antonio. The rules were the same here, albeit much more was at stake than an arbitrary collection of points.

The debris began to creak and shift. An infinitesimal hole began to form. The girls would have to crawl through it—they must, she thought. Any more movement of the wood and the structure would come crashing down like an encroaching tide.

“Hurry! You have to come now.” Vee demanded. “You’ll have to crawl through.”

The girls scaled the splintered woodpile making their way toward the exit. For the first time Vee saw the first girl’s face, peeking through the branches. Her face was familiar. Perhaps she had seen her around town. Perhaps it was in a different world. A world in which her daughter was still with her. It would have been at her daughter’s school at the front entrance under the green awning. The girl would have on a denim JanSport bag—staring at the ground and waiting to be picked up.

“Lady? Lady?” The girl shouted. Vee regained focus and pulled the child to safety. She was so light—almost ethereal. The girl plopped down beside Vee in the soupy living room.

The other girl was next. Twins, Vee thought. They each shared deep brown eyes and freckles splattered across their faces like paint.

The second girl had something the other did not, though. Her right arm was an amalgam of reds, blues, and purples. Her hand was contorted, twisted—unrecognizable. It must have happened when the tree fell on the house. Why wasn’t she screaming with pain? Where are their parents? Were they with them when the storm made landfall?

Vee grabbed the girl’s uninjured hand and pulled her toward her chest. For the first time in months, Vee felt a semblance of meaning in her life—a freeing from the suffocation of this hurricane season. Something present that had been lost in the waters.

Lifting the two girls onto her shoulders, Vee navigated the transient sea that had formed in the living room, and headed toward the mauve front door.

Vee and the twins stumbled out of the house and into the flood.

A ringed kingfisher perched on a slanted telephone line—its feathers iridescent in the sliver of peach sunlight. Their eyes locked for only a second. Although it would not be the last, the storm—like this moment—would soon pass.

A 1.5°C cap to global warming could greatly benefit Europe

New research shows that limiting warming to 1.5°C would reduce the frequency of extreme heat and rainfall across Europe.

This is compared to a previously sought 2°C limit to global warming. Many scientists now say a 2°C cap is not enough, and would place extreme stress on many of the world’s most sensitive ecosystems. A 0.5°C difference may seem insignificant, but it could make all the difference in avoiding record-breaking heat waves.

Researchers at the University of Melbourne and the University of Oxford used simulations—called coupled climate models—to show that 1.5°C of global warming would make extreme heat waves in Europe less likely to occur.

“For example, we found that events similar to the European heat wave of 2003, which caused tens of thousands of deaths, would be 24% less frequent in a world at 1.5°C global warming compared to 2°C global warming,” say the researchers.

Changes in rainfall were also included in the climate models. Although the changes are less pronounced compared to warming, they could still have major consequences for European countries.

“There is an increase in the frequency of very wet days like those seen during May–July 2007 over the UK and Ireland. In a 2°C world, such extreme rainfall events are at least 17% more likely than in a 1.5°C world.”

In England alone, the economic cost of damage to property from the Summer 2007 floods was estimated at $4 billion. If a 2°C threshold is reached, Europe could expect flooding damage like this once every 10 years.

The Paris Agreement—an international effort to keep global warming below 2°C and to attempt to cap the warming further to 1.5°C—has recently sparked a wave of studies examining what’s needed to achieve this cap. Many of these studies now suggest that negative emissions, removing carbon dioxide from the atmosphere, are needed to keep global warming below 2°C, which is becoming increasingly unlikely.

This failure to limit global warming could have considerable consequences for Europe.

“In future scenarios of 1.5°C and 2°C warming, heat extremes become considerably more frequent,” the authors of the current study say. “Even at only 1.5°C of warming we estimate that hot years across Europe, like 2016, the hottest year on record, would happen roughly one-in-every-two years.”