Saturday, August 20, 2016

What Would Happen if we Abandoned Britain's Farms and Left Them to Nature?

Now what? David Hughes/Shutterstock
by Christopher Sandom, University of Sussex, The Conversation: https://theconversation.com/what-would-happen-if-we-abandoned-britains-farms-and-left-them-to-nature-63951

Without farming, Britain’s countryside would be drastically different. Imagine walking through landscapes un-tilled, un-sown, un-fertilised and un-treated, nor grazed by cattle or sheep.

Following the Brexit vote, the government has to decide what to do about the Common Agricultural Policy (CAP), the EU’s subsidy scheme for owners of farmed land.

Some of these subsidies support food production while others support environmental protection on land suitable to be farmed. In 2015, British farmers received roughly £3.2 billion from the EU.

Agricultural land covers 70% of the UK. If all subsidies stopped, the National Farmers Union reports many farmers would go out of business and large swathes of land would come out of production.

This may be unlikely (and it’s certainly not what I’d recommend) but it’s still worth exploring an even more dramatic scenario: what would happen if Britain’s farmers sold all their livestock and equipment and abandoned their land?

There would be cultural, social and economic shock for sure. With less food grown and reared locally, prices would undoubtedly rise as supermarkets scrambled to secure foreign supply lines. But what would happen to the land itself? Without farming, what would happen to Britain’s nature?

Scenario one: land abandonment

With the hungry mouths of livestock gone, along with the farmer’s ploughs, the great wheels of ecological succession would be freed to turn. Ecological “succession” is the process of change from one set of species to another. In this case, it would begin with dormant seeds, native or otherwise, that would start to emerge. Plants best adapted to fertilised soil such as nettles will thrive.

In time, shrubs and trees will venture into abandoned fields from woodland and hedgerows. Then would come fast growing, light-demanding trees like birch and oak, turning scrubland into early phase woodland. In the shade of the new canopy, lime and elm, both tolerant of low light conditions, will slowly establish themselves until they outlive or outgrow the trees that came before them.

It is a textbook story of succession. The varying climates and soils across Britain mean different species will prosper in different places, and plants will grow at different paces, but in time, in most places, the result will be largely the same. More trees.

England’s green and pleasant lands would mostly look something like this – eventually. ukgardenphotos, CC BY-NC-SA

Herbivores could halt this process in places, and roe, sika and red deer populations would be likely to thrive post-farming. But Britain is missing the heavy-duty herbivores like aurochs (the ancestor of domestic cows) and wild horses that can help halt succession. Storms and fire would open up the canopy in other places, but it is likely that woodland would come to dominate eventually.

So how would this affect Britain’s wildlife more broadly? We can look to the past for insight. Agriculture arrived in Britain around 5,000 years ago. Early farmers cleared woodland to allow them to graze cattle and grow crops. The result of this transition was that plants and animals that favoured open areas thrived. Woodland associated species suffered. In fact, most of the known recent extinctions in Britain are of woodland species, such as the red-backed shrike or scarce dagger moth.

Farmland abandonment would reverse this trend. Species associated with open habitats, such as grey partridge, skylark, lapwing, as well as many bees and butterflies, would find fewer places that meet their needs. But scrub and woodland species, such as bullfinch, nightingale, and capercaillie birds, as well as other groups like moths, beetles, fungi and mammals would thrive once more.

Bullfinches would flourish without farms. f.c.franklin, CC BY-SA

Scenario two: trophic rewilding

What would happen if instead of just abandoning the land, populations of large herbivores such as bison, wild horse, European elk (aka moose) or wild boar were established, along with their predators lynx, wolf and bear?

This scenario is known as “trophic rewilding”. The starting processes would be similar, and succession would still swing into action. But the shrubs and trees trying to establish in fields will be grazed and browsed. Areas of intense grazing would stay open.

But even large herbivores can be less inclined to browse where spiky bushes of bramble, hawthorn and gorse have established. Predators too will mean some areas are relatively free from large plant eaters, who would soon learn to avoid places where they feel at greater risk of being eaten. These plant havens would allow trees to grow, eventually poking out from the protective cocoon of spikes, to emerge above the browsing height of herbivores.

This combination of vegetation-driven processes rising from the bottom of the food-web and predator and herbivore driven processes cascading down from the top can create rich mosaics of habitats. Some of these habitats would be open grasslands full of wildflowers, others mighty woodlands, and some caught in transition. These different habitats would provide for the full range of Britain’s plants and animals.

But, as far as I know, Britain’s farmers have no plans of quitting. Plus, Britain’s nature is well worth investing in to secure our food supply, safeguard biodiversity and restore resilient ecosystems that support society. But this juncture gives us a chance to think about our future and perhaps, in some places, the return of wild nature should be welcomed.

Christopher Sandom, Lecturer in Biology, University of Sussex

This article was originally published on The Conversation. Read the original article.

Friday, August 19, 2016

From Epic Fires to a 1,000-Year Flood: The Climate Change of Here and Now

The Blue Cut fire burns near Phelan, California (Reuters)
by Deirdre Fulton, staff writer, Common Dreams: http://www.commondreams.org/news/2016/08/18/epic-fires-1000-year-flood-climate-change-here-and-now

From deadly floods in Louisiana to an "explosive" wildfire in California, the impacts of the climate change are being felt across the United States this week.

Neither extreme weather event can be exclusively blamed on global warming. But record-breaking heat, warmer oceans, and drier brush - all linked to man-made climate change - are certainly contributing factors.

"Climate change is never going to announce itself by name. But this is what we should expect it to look like," declared Jonah Engel Bromwich at the New York Times, referring to the flooding in southern Louisiana, which has been called the worst natural disaster to strike the U.S. since Superstorm Sandy.

In fact, current analyses suggest that - as was the case in 2012 - greenhouse gas emissions and resultant climate change at the very least increased the severity of the storm that brought on the flooding.
InsideClimate News reported Wednesday:
Of the two factors that made Louisiana's storm so devastating, one (increased moisture in the air) wears the fingerprints of man-made climate change from mostly fossil-fuel burning, while the other (how slowly the storm was moving) is not so easily explained. "This storm is a good example of why we care about a changing climate," said Katharine Hayhoe, a climate scientist at Texas Tech University, "because Louisiana is a place that is already at risk of flooding and climate change is taking the risk that we already face, and it's exacerbating" the threat [...] "with such a warm year, you're going to see much higher-than-average sea surface temperatures," Hayhoe said. Those water temperatures, in this case the Gulf of Mexico where the storm system formed on Aug. 7, mean the air above it has more than its usual share of water vapor, Hayhoe explained. 
Added Weather Underground's Bob Henson and Jeff Masters in a blog post on Monday:
The storm system carried near-record amounts of atmospheric moisture, drawn from the Gulf of Mexico and northwest Atlantic, where sea-surface temperatures are well above average. Climate change has already been shown to increase the amounts of rain falling in the most intense events across many parts of the world, and extreme rainfall events like this week's Louisiana storm are expected to grow increasingly common in the coming years.
Indeed, wrote Gulf Coast mother and activist Cherri Foytlin on Thursday, "This type of storm is far from normal - but it could become normal if we don't act now. Across the region, tens of thousands of people have been evacuated, thousands of homes damaged, and at at least eleven people killed," wrote Foylin, who serves as state director of climate action group Bold Louisiana. "This fills my heart with both a deep sadness and deep anger - at the fossil fuel companies driving this ongoing crisis, and at an [Obama] administration that continues to sell them the right to do so."

As evidence, Foytlin pointed to the looming auction of "an area the size of Virginia for offshore drilling in the Gulf of Mexico" - and called for President Barack Obama to call off the auction "and stop treating the Gulf Coast like a sacrifice zone."

Meanwhile, on the West Coast, the Blue Cut fire now covers close to 50 square miles, threatening more than 34,000 structures and forcing the evacuation of more than 82,500 people. California Gov. Jerry Brown has declared a state of emergency for the fast-moving wildfire, which was only 4 percent contained as of early Thursday morning. This event, too, can be linked to global warming. As the Union of Concerned Scientists has written:
Higher spring and summer temperatures and earlier spring snow-melt typically cause soils to be drier for longer, increasing the likelihood of drought and a longer wildfire season, particularly in the western United States. These hot, dry conditions also increase the likelihood that, once wildfires are started by lightning strikes or human error, they will be more intense and long-burning.
"Climate change has exacerbated naturally occurring droughts, and therefore fuel conditions," Robert Field, a research scientist at NASA's Goddard Institute for Space Studies," told Climate Central earlier this year.
And the New York Times reported Wednesday:
Richard Minnich, a professor in the department of earth sciences at the University of California, Riverside, said it was not so much the long-term drought, but the weather of the day - coupled with a prevailing fire management strategy in which, he said, small fires are knocked down quickly but larger ones can grow more out of control - that had driven the fire. The low humidity, Mr. Minnich said, had dried out shrubs and bushes - known as chaparral - making them as flammable as a carpet. “It’s got a reputation for burning explosively,” he said of the chaparral, adding, “As soon as it’s blowing up like that, the capacity to stop the fire goes to zero.”
Furthermore, a new Yale-led study conducted with collaborators from Harvard showed just this week that "a surge in major wildfire events in the U.S. West as a consequence of climate change will expose tens of millions of Americans to high levels of air pollution in the coming decades."

As an observer noted on Twitter, with more than 80,000 people currently under evacuation orders in California and 30,000 more displaced in Louisiana, "one might say there are over 100k climate refugee[s] in the US right now."