tropical regions

Species and climate change

July 4, 2024 By EarthWise Leave a Comment

Temperature extremes on Earth currently range from a low of -129°F to a high of 134°F. But these climatic limits have changed throughout history. In fact, during the last interglacial period 130,000 years ago, temperatures were warmer, resembling what we are projected to experience at the end of this century.

Species that evolved during such periods may possess pre-adaptations that could help them tolerate upcoming changes to the climate. This factor is often overlooked by traditional statistical models predicting species’ responses to climate change.

But a new model, developed by researchers from Ifremer in France and Lausanne University in Switzerland, has taken this oversight into account, and reassessed the proportion of terrestrial and marine species threatened with extinction by climate change.

In the study, which was recently published in the journal Nature Ecology and Evolution, the research team applied its model to nearly 25,000 terrestrial and marine species from around the world. The researchers discovered that 49% of these species live in climate niches near the current climatic limits, and 86% could potentially extend beyond these limits.

The most surprising result concerns tropical regions. While forecasts from traditional models estimate that the diversity of terrestrial species in tropical areas could decrease by 54% between now and 2041-2060, the new model predicts a more moderate decline of 39%.

The findings confirm the importance of taking urgent measures to mitigate climate change and its impact on biodiversity.

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Some species may better tolerate climate change than expected

Photo, posted October 23, 2015, courtesy of Anita Ritenour via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Coffee, cocoa, and pollinators

November 20, 2023 By EarthWise Leave a Comment

Multiple forces have been at play that have been detrimental to pollinators including climate change, land use change, pesticide use, and more. There have been substantial declines in both the abundance and diversity of insect pollinators. There is increasing public awareness of this issue, but it hasn’t really risen all that high among many people’s concerns.

A new study by University College London looked at the effects of the global decline in pollinators on thousands of crop-growing sites around the world involving thousands of insect pollinator species.

About 75% of all crops grown depend on pollinators to some degree. The UCL research created a model that looks at which pollination dependent crops are most threatened over the next 30 years in order to provide a warning to both the agricultural and conservation communities.

The research indicates that the tropics are likely to be most at risk with regard to reduced crop production caused by pollinator losses. This is mostly due to the interaction of climate change and land use. The risks are highest in sub-Saharan Africa, northern South America, and southeast Asia.

These areas are where the world gets most of its coffee and cocoa, two crops that are near and dear to most of us. These crops, as well as others such as mangoes, play vital roles in both local economies and global trade and reducing them could lead to increased income insecurity for millions of small-scale farmers in these tropical regions.

If pollinator loss isn’t high up on your list of global concerns, perhaps you should think about it next time you have a cup of coffee or enjoy some chocolate.

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Coffee and cocoa plants at risk from pollinator loss

Photo, posted May 23, 2013, courtesy of McKay Savage via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Insects In A Changing Climate | Earth Wise

October 27, 2022 By EarthWise Leave a Comment

Insects can be found in every environment on Earth and are critical components of many ecosystems. They perform countless important functions, including aerating and fertilizing soil as well as pollinating flowers. In fact, according to the USDA, 75% of the world’s flowering plants and about 35% of the world’s food crops depend on animal pollinators, the majority of which are insects, to reproduce.

According to a study published in the journal Nature earlier this year, the combination of climate change and intensive agriculture is having a profound impact on both the abundance and diversity of insects. In regions where substantial warming had occurred and where land had been converted for intensive farming, insects were nearly 50% less abundant and more than 25% fewer species were observed. Tropical regions were among those most at risk for heavy losses.

According to a new study recently published in the journal Global Change Biology, tropical insects will be even more susceptible to climate change than previously thought. In a five-year study conducted in Peru, researchers from the Florida Museum of Natural History found that insect populations declined 50% following short periods of drought and following short periods of heavy rainfall. Insect populations decreased after three months of dry weather, but also decreased after three months of exceptionally wet weather.

Researchers have known that tropical insects don’t tend to do well when their habitats dry out. But the researchers were surprised to discover that these insects were equally averse to increased precipitation. Alarmingly, precipitation is expected to become more frequent and more intense as a consequence of the changing climate.

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Tropical insects are extremely sensitive to changing climates

Photo, posted June 11, 2016, courtesy of Z. Leng via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Russian Forests And Climate Mitigation | Earth Wise

August 24, 2021 By EarthWise Leave a Comment

Russia is the largest country in area in the world, almost equal in size to the sum of the next two largest – Canada and the U.S. Russia is also the world’s largest forest country, containing more than one-fifth of the world’s forests. As a result, the country’s forests and forestry activities have enormous potential for impacting climate mitigation.

Since the dissolution of the USSR, there has been a decline in the availability of information on the state of Russia’s forests. The Soviet Forest Inventory and Planning System compiled information until 1988. Since then, the Russian National Forest Inventory has been the source of forest information on the national scale, and it hadn’t produced a comprehensive inventory until 2020.

The new data indicates that Russian forests have in fact accumulated a large amount of additional biomass over the intervening years. Using the last Soviet Union report as a reference point, the new results show that the ongoing stock accumulation rate in Russian forests over the 26-year period is of the same magnitude as the net forest stock losses in tropical countries.

Thus, it is clear that Russian forests have great potential in terms of global climate mitigation as well as potential co-benefits relating to the green economy and sustainable development. It is important to note that as the impact of climate change increases, disturbances to the Russian forests could have severe adverse effects on global climate mitigation efforts.

While much of the world’s attention is rightfully upon tropical rainforests in the Amazon and elsewhere, it is important to not ignore the largest country in the world hosting the largest land biome on the planet where even small percentage changes in the amount of forest biomass could have a major global impact.

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Russian forests are crucial to global climate mitigation

Photo, posted June 6, 2015, courtesy of Raita Futo via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Engineering Mosquitoes | Earth Wise

February 21, 2020 By EarthWise Leave a Comment

Tropical regions grapple with the spread of diseases – such as dengue, yellow fever, zika, chikungunya, and malaria – by mosquitoes. A fairly successful strategy has been the Sterile Insect Technique, which is essentially insect birth control. The process involves rearing large quantities of sterilized male mosquitoes in dedicated facilities, and then releasing them to mate with females in the wild. As they do not produce any offspring, the insect population declines over time.

A problem with this approach is that while mosquitoes create health problems for people, they also play important roles in various ecosystems, such as providing food for bats and other animals. Eliminating mosquito populations on a large scale can trigger major changes in ecosystems.

Recently, an international team of scientists has synthetically engineered mosquitoes that halt the transmission of the dengue virus. They genetically engineered mosquitoes with an antibody “cargo” that gets expressed in the female mosquitoes that spread the dengue virus. Once the female mosquito takes in blood, the antibody is activated which hinders the replication of the virus and prevents its dissemination throughout the mosquito, thereby preventing its transmission to humans. Essentially, what the researchers have done is transfer genes from the human immune system to confer immunity to mosquitoes. The researchers are testing methods to neutralize mosquitoes against other viruses they spread.

This opens up a whole new approach to interrupt mosquito-borne human diseases. Mosquitoes are among the deadliest killers on the planet because they are the messengers that transmit deadly diseases. Until now, the only real solution has been to kill the messenger. The new approach may be a better way to deal with a serious problem.

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Mosquitoes engineered to repel dengue virus

Photo, posted June 20, 2014, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Widespread Local Extinctions

January 17, 2017 By EarthWise

Plants and animals have evolved over time to live in specific environmental niches. As the climate warms, parts of the ranges in which they live may no longer offer the conditions under which they can thrive. Species can respond to these changes in three ways: they can adapt to new conditions by undergoing niche shifts; they can relocate to better conditions, such as by moving to higher elevations or latitudes; or they can locally go extinct.