https://www.cnn.com/2024/02/13/climate/greenland-ice-loss-vegetation-climate-intl/index.html
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“Humanity now stands at Peak Farmland, and the 21st century will see release of vast areas of land, hundreds of millions of hectares, more than twice the area of France for nature,” declared Jesse Ausubel, the director of the Program for the Human Environment at Rockefeller University, in a December lecture. Ausubel was outlining the findings in a new study he and his collaborators had done in the Population and Development Review . Unlike other alleged resource “peaks,” peak farmland reflects not the exhaustion of resources but the fruits of human intelligence and growing affluence.
The trend toward reducing farming’s impact on nature took off with the Green Revolution of the 1960s…If global crop yields had remained stuck at 1960 levels, Ausubel noted in his lecture, farmers around the world “would have needed about 3 billion more hectares, about the sum of the USA, Canada, and China or almost twice South America.”…
What about the future? The researchers offer a 50-year forecast via their ImPACT equation, which calculates how much land will be used for crops (Im) by multiplying population trends (P), affluence (A) as GDP per capita, consumption (C) as calories per GDP, and technology (T). The United Nations expects population growth to continue to slow, global affluence to increase at around 1.5 percent per year, people to spend relatively less on food as their incomes rise (Engel’s law), and the amount of crop per each hectare to rise by 2 percent annually. (In aggregate, farmers today can produce nearly three times the food they did in 1960 on the same amount of land.) The authors also take into account the growing global desire for meat, which means growing more grains to feed animals, and the diversion of crops into other non-food products such as biofuels…
Cranking various population, economic growth, and yield trends through the ImPACT equation, the authors conservatively conclude that in 2060 “some 146 million hectares could be restored to Nature, an area equal to one and half times the size of Egypt, two and half times France, or ten times Iowa.” Under a slightly more optimistic scenario’"one where population growth slows a bit more, people choose to eat somewhat less meat, agricultural productivity is modestly higher, and there’s less demand for biofuels’"would spare an additional 256 million hectares from the plow. That would mean nearly 400 million hectares restored to nature but 2060, an area nearly double the size of the United States east of the Mississippi River.
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No matter how you slice It change is constant. It is great that experts anticipate trends and try to identify needs.
Global warming is expected to bring drought and water shortages in some regions. Increase temperate growing season in some areas. Thaw some frozen regions. Probably affect fishing and all sorts of livestock as well as wild animals. Plus sea rise, flooding, and storms.
Research has time to decide which new crops or new varieties are needed. Maybe to develop new ones that fit climate changes. Major changes may require investment and helping farmers learn new methods. Tremendous progress has been made but more change seems inevitable.
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It is not making up for the land loss in Louisiana. Underwater: Land loss in coastal Louisiana since 1932 | NOAA Climate.gov
Every year, 25-35 square miles of land off the coast of Louisiana—an area larger than Manhattan–disappears into the water due to a combination of subsidence (soil settling) and global sea level rise. These maps show how much land has been lost to the Gulf of Mexico in the past 80 years.
The first image in the animation shows the state of the coast in 2011. Based on a NASA satellite image, gray and white areas show land and blue indicates open water. New land—mainly coastal improvements such as shoreline revetments and enriched beach areas—that built up since 1932 is shown in green. The second image shows the state of the coast in 1932. The image combines the 2011 satellite image with a U.S. Geological Survey map in which land areas that were present in 1932 are light gray. Since the 1930s, Louisiana’s coast has lost 1,900 square miles of land, primarily marshes.
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Coastal areas were also analysed, and to the scientists surprise, coastlines had gained more land - 33,700 sq km (13,000 sq miles) - than they had been lost to water (20,100 sq km or 7,800 sq miles).
“We expected that the coast would start to retreat due to sea level rise, but the most surprising thing is that the coasts are growing all over the world,” said Dr Baart.
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From the article, any coastal ‘gain of land’ came from human construction of islands, in Dubai and China. More net ‘gain of land’ came from inland drought and loss of reservoirs due to irrigation and water use by cities.
Loss of land is still caused by melting glaciers and polar ice.
The article appears to say that ice and glaciers are still melting and water is moving in surprising and destructive ways; with rising sea levels around the world, melting inland glaciers, and increased storm damage.
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The paper says that the “largest coastal water–land change is the construction of the Palm Island and adjacent islands along the coast of Dubai…” The increase in Dubai was 80 sq. km. Pretty small contribution out of a land increase of 33,700 sq. km.
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The “largest coastal-water land change…”
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Let’s not forget the Aral Sea, the world’s fourth-largest lake, drained dry and now accounting for an inland ‘land change’ of 27,841 square km: 82.6% of the worldwide ‘land change.’
So, we’re saying worldwide coastal waters are not rising when we add the land under the world’s fourth-largest lake?
That’s reframing the argument from whether sea levels are rising to whether sea levels and all other water levels are rising in comparison to all dry land.
Apples to oranges.
By that line of reasoning, we’ll be fine if we can keep drying up lakes! And we’re doing our best with Lake Mead, the largest fresh water supply in the US.
Sheesh.
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Sheesh indeed. The researchers separated out changes in things such as lakes and reservoirs from coastal change. “The largest coastal water–land change is the construction of the Palm Island and adjacent islands along the coast of Dubai (80 km2…)”
“We expected that the coast would start to retreat due to sea level rise, but the most surprising thing is that the coasts are growing all over the world,” said Dr Baart.
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He also said, " “We’re were able to create more land than sea level rise was taking.”
Image source, deltares
Image caption,
In Dubai, the creation of new islands has significantly altered the coastline
The researchers said Dubai’s coast had been significantly extended, with the creation of new islands to house luxury resorts.
“China has also reconstructed their whole coast from the Yellow Sea all the way down to Hong Kong,” said Dr Baart.
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We appear to be building our way out of the ocean’s rise.
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Abstract:
A shoreline change data base for Florida dating back to the mid-1800s is unique in the United States, and perhaps the world, with thousands of shoreline change measurements at a nominal spacing of 300 m. Moreover, data are available on factors contributing to shoreline change, including beach nourishment, disposal of dredged sand outside the littoral zone, cutting of new inlets and subsequent growth of ebb shoals, and longshore sediment transport into and along the east coast of Florida. Effects of relative sea level rise can be estimated using the Bruun Rule. These factors should have caused significant shoreline recession since the mid-1800s, but instead, the east coast of Florida has experienced significant average shoreline advance. The formation of carbonate sand is shown not to account for this difference. Onshore transport of sand from beyond closure depth, probably during episodic storm events, is the only possible source of the large quantity of sand that has advanced on average the shoreline of Florida’s east coast. For shorelines with significant offshore deposits of sand, it is possible that sea level rise in conjunction with wave action contributes to onshore transport and shoreline accretion.
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Good news for islands. Zhang et al. assessed over 13,000 islands for coastal change over 30 years (1990-2020). Some 6% gained, 7.5% lost and the vast majority were stable.
Sea level rise was a factor but not a predominate one. This was “contrary to initial assumptions”.
“Moreover, the data results suggest that sea-level rise has not been a widespread cause of erosion for island shorelines in the studied region. Presently, it is considered one of the contributing factors to shoreline erosion but not the predominant one.”
Overall, there was a net increase in island area over the three decades.
Evolutionary dynamics of island shoreline in the context of climate change: insights from extensive empirical evidence
https://www.tandfonline.com/doi/pdf/10.1080/17538947.2024.2329816
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This is what the authors of the linked paper concluded:
"Based on a thorough analysis of current data and consideration of future sea-level scenarios, we believe that sea-level rise will continue to pose a significant challenge to island communities and recommend these communities to adopt scientifically validated strategies as these could be crucial for their sustainable survival and development. On the other hand, failing to adapt proactively or resort to short-lived and hasty measures could lead to severe consequences for small island states and regions."
And at the same time, they found their results “contrary to initial assumptions”. This could well happen again, with sea level rise not a predominate factor.
At any rate, during the last three decades over 90% of the 13,000+ islands were either stable or growing. To repeat, good news about islands.
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