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Climate change could cause more severe droughts in ‘98% of European cities’

More than 500 European cities could face sharp increases in droughts, floods and heatwaves if climate change continues to rise unabated, a new study finds.

The UK and Ireland could experience the largest rise in urban flood risk out of any region in Europe, the research shows, while the greatest heatwave temperature increases could be felt in Austria and Germany.

The findings also show that more than 100 cities could face a rise in the risk of two or more types of extreme event by the second half of the century, with Leeds, Cardiff and Exeter featuring in the top 20% of cities at risk of both heatwave and flooding increases.

The study is “an example of what might happen if we don’t start cutting our carbon emissions in a timely fashion”, a scientist not involved in the study tells Carbon Brief.

City concerns

More than 75% of the European Union’s population live in urban areas and this figure is expected to rise to 82% by 2050.

The new study, published in Environmental Research Letters, estimates how climate change could affect the risk of flooding, drought and heatwaves in 571 European cities by the second half of the century.

For the study, the researchers used a collection of climate models to simultaneously assess the risk of floods, droughts and heatwaves for every city.

Glossary

RCP8.5: The RCPs (Representative Concentration Pathways) are scenarios of future concentrations of greenhouse gases and other forcings. RCP8.5 is a scenario of “comparatively high greenhouse gas emissions“ brought about by rapid population growth, high energy demand, fossil fuel dominance and an absence of climate change policies. This “business as usual” scenario is the highest of the four RCPs and sees atmospheric CO2 rise to around 935ppm by 2100, equivalent to 1,370ppm once other forcings are included (in CO2e). The likely range of global temperatures by 2100 for RCP8.5 is 4.0-6.1C above pre-industrial levels.

RCP8.5: The RCPs (Representative Concentration Pathways) are scenarios of future concentrations of greenhouse gases and other forcings. RCP8.5 is a scenario of “comparatively high greenhouse gas emissions“ brought about by rapid population growth,… Read More

Using a high-emission pathway known as RCP8.5, the models produced “low”, “medium” and “high” impact scenarios for each location.

The researchers estimated changes in risk by comparing the likelihood of extreme events from 1951-2000 to a future period of 2051-2100.

The research shows that every European city will face an increase in extreme weather event risk as the climate warms, says lead author Dr Selma Guerreiro, a researcher in hydrology and climate change from the University of Newcastle. She tells Carbon Brief:

“The British Isles have some of the worst overall flood projections. Southern European cities will see the biggest increases in the number of heatwave days. However, the greatest heatwave temperature increases are expected in central European cities.”

Heating up

Global warming is expected to cause an increase in the number of people exposed to heatwaves in the coming centuries.

The new research defines heatwaves as three consecutive nights where temperatures are in the top 5% of the 1951-2000 average for each city.

The maps below show how the proportion of heatwave days in the summer (top) and maximum temperature (bottom) of heatwaves could change in European cities under a low, medium and high-impact scenario. On the maps, each dot shows the results for one city – with impacts ranging from small (green) to large (dark red) increases.

Change in the proportion of heatwave days in the summer (left) and maximum heatwave temperature (right) in European cities in 2051-2100 compared to 1951-2000 under a low (left), medium (middle) and high (right) scenario. Source: Guerreiro et al. (2018)

The research finds that both the number and maximum temperature of heatwaves is likely to increase for every city under all of the scenarios.

Cities in southern Europe are expected to see the greatest increase in the number of heatwave days per year, with Lefkosia and Lemesos in Cyprus facing a 69% in heatwave days by 2050 under the high scenario.

Meanwhile, the largest increases in maximum heatwave temperature are expected to occur in central European cities, with some areas experiencing a rise of 14C above previous maximum temperatures. Under the high scenario, 72% of European cities could see an increase in maximum heatwave temperature by 2050.

Projections under the high scenario also suggest that cities in the UK could face maximum heatwave temperature increases of up to 12C as the climate warms, says Guerreiro:

“The UK is less affected than most of continental Europe for the low-impact scenario, where UK cities can expect changes in maximum temperature during a heatwave between 2C and 5C. However, for the high-impact scenario the maximum temperature during a heat-wave for UK cities could increase from 7C to 12C.”

Drying out

Changing rainfall patterns as a result of climate change is expected to lead to more droughts in some parts of Europe.

For the study, the researchers used a measure known as the drought severity index (DSI), which gives a picture of drought risk over a one-year period.

The charts below show the probability of drought risk for each city in 2050, when compared to risk from 1951-2000. On the maps, light blue indicates no change, while yellow shows a small increase and dark red shows a high increase.

Probability of drought risk in European cities in 2051-2100, compared to risk from 1951-2000. Light blue indicates no change, while yellow shows a small increase and dark red shows a high increase. Source: Guerreiro et al. (2018)

The findings show that the largest increases in drought risk are expected to affect southern European cities, including Lisbon and Faro in Portugal and Seville and Barcelona in Spain, says Guerreiro:

“For the low-impact scenario, cities in the south of Iberia, such as Malaga and Almeria, are expected to experience droughts that are more than twice as bad as today. While for the high impact scenario, 98% of European cities could see worse droughts in the future.”

The research also shows that, under the high-impact scenario, 21 cities in southern Europe may experience droughts that are up to 14 times worse than the extreme droughts of 1951-2000.

Spilling over

Climate change is expected to cause an increase in flood risk in much of Europe, although the scale of this impact is likely to affected by a range of factors, such as urban planning.

To understand changes in flood risk, the researchers estimated changes to maximum river flow (or “discharge”) over a ten-year return period for each city.

This shown on the chart below, where green shows a small increase in river flows and dark red shows a large increase.

Changes in river flow (discharge) over a ten-year return period in European cities in 2051-2100, compared to 1951-2000. Green shows a small increase in flood risk and dark red shows a large increase in flood risk. Source: Guerreiro et al. (2018)

The findings show that cities in the UK and Ireland could face the largest increase in river flows out of any region in Europe, with Glasgow, Wrexham, and Aberdeen being among the most at-risk cities.

Under the low scenario, 85% of UK cities could face increased river flooding, says Guerreiro:

“The British Isles are a future hotspot for river flooding in Europe. The cities predicted to be worst hit under the high-impact scenario for the British Isles are Cork, Derry, Waterford, Wrexham, Carlisle, and Glasgow. For the low-impact scenario, Derry, Chester, Carlisle, Aberdeen, and Glasgow could be worst affected.”

‘Substantial challenge’

The findings also show that more than 100 cities in Europe could face a rise in the risk of two or more types of extreme event by the second half of the century.

In the UK, Cardiff, Exeter, Leeds and Newport fall within the top 20% of European cities at risk of both heatwave and flooding increases as the climate warms, Guerreiro says:

“We hope to highlight the substantial challenge cities face in managing climate risks and provide an encompassing view of possible future changes in climate.”

The new research advances our understanding of extreme weather risks in European cities by “considering all these hazards together,” says Dr Dann Mitchell, a researcher in climate change, extreme events and human health at the University of Bristol, who was not involved in the study.

However, it is worth bearing in mind that the research uses a high emissions trajectory for its analysis, he tells Carbon Brief:

“It would also be interesting to see how sensitive their analysis is to other greenhouse gas emissions. The emission scenario used in their study is much higher than that which would be consistent with the Paris Agreement and so their study could be thought of as an example of what might happen if we don’t start cutting our carbon emissions in a timely fashion.”

The post Climate change could cause more severe droughts in ‘98% of European cities’ appeared first on Carbon Brief.

Every five-year delay in meeting Paris goals could ‘add 20cm’ to global sea levels

Failure to meet the goals of the Paris Agreement within the next few decades could have long-lasting impacts on global sea level rise in the coming centuries, new research finds.

A study finds that each five-year delay in meeting the goal of reaching global peak CO2 emissions could drive sea levels to rise by an additional 20cm by 2300.

This amount of sea level rise is roughly equal to what the world has experienced since the start of the industrial revolution more than 200 years ago, the lead author tells Carbon Brief.

The findings reiterate that “peaking global CO2 emissions as soon as possible is crucial for limiting the risks of sea level rise”, the author adds.

Race to zero

Samples taken from ice cores, tide gauges and satellites show that global sea levels have risen by around 19cm from pre-industrial times to present, with recent research showing that the rate is likely to be accelerating.

The new study, published in Nature Communications, estimates how delays in meeting the goals of the Paris Agreement could affect the total amount of sea level rise by 2300.

Under the Paris Agreement, countries have pledged to cut their rates of emissions in order to keep future global temperature rise “well below” 2C. To achieve this, nations agreed to reach “peak” CO2 emissions “as soon as possible”. This will be key to achieving “net-zero emissions” within the second half of this century.

The new research shows that the speed at which the world can cut its greenhouse gas emissions is becoming “the major leverage for future sea levels,” says study lead author Dr Matthias Mengel, a postdoctoral researcher from the Potsdam Institute for Climate Impacts (PIK) in Germany. He tells Carbon Brief:

“The way that emissions will evolve in the next decades will shape our coastlines in the centuries to come: five years of delayed [CO2] peaking will lead to 0.2 metres more sea level rise in 2300. This is the same amount we have experienced so far since the beginning of the fossil economy.”

Melting prospects

Glossary

RCP2.6: The RCPs (Representative Concentration Pathways) are scenarios of future concentrations of greenhouse gases and other forcings. RCP2.6 (also sometimes referred to as “RCP3-PD”) is a “peak and decline” scenario where stringent mitigation and carbon dioxide removal technologies mean atmospheric CO2 concentration peaks and then falls during this century. By 2100, CO2 levels increase to around 420ppm – around 20ppm above current levels – equivalent to 475ppm once other forcings are included (in CO2e). By 2100, global temperatures are likely to rise by 1.3-1.9C above pre-industrial levels.

RCP2.6: The RCPs (Representative Concentration Pathways) are scenarios of future concentrations of greenhouse gases and other forcings. RCP2.6 (also sometimes referred to as “RCP3-PD”) is a “peak and decline” scenario where stringent mitigation… Read More

For the study, the researchers used climate models to simulate future sea level rise by 2300 under two future scenarios. Both of the scenarios assume that the world will meet the Paris goals by the end of century and use a low-emission pathway known as RCP2.6.

The first scenario, called “net-zero greenhouse gas (GHG) emissions”, assumes that future temperature rise will be limited to well below 2C and a balance between emissions and uptake of greenhouse gases is met by the end of the century.

The second scenario, called “net-zero CO2 emissions”, is a future in which temperatures are stabilised at levels well below 2C but GHG emissions are not balanced by the end of the century. This scenario allows for the potential “overshoot” of the temperature targets before stabilisation, which some scientists suggest is likely.

The researchers used these scenarios to work out possible future global temperatures and applied them to a model of long-term sea level rise.

Global warming causes sea levels to rise in three main ways, Mengel says: “thermal expansion”, when seawater expands as the oceans absorb additional heat from the atmosphere; melting glaciers; and ice loss from the large ice sheets of Greenland and Antarctica.

The model incorporates recent research (pdf) finding that the Antarctic ice sheet may be more sensitive to climate change than previously thought, Mengel says:

“The contribution from Antarctica increases with warming, faster than all other components.”

Closing window

The charts below show the expected CO2 emissions, temperature rise and sea level rise for the net-zero CO2 emissions scenario (a-c) and the net-zero GHG emissions scenario (d-f).

On the charts, coloured lines and symbols are used to indicate the expected outcomes of reaching peak CO2 emissions in five-year intervals from 2020 to 2035. Scenarios that do not limit global warming to 2C are shown in thin grey lines.

Shading shows the 66th percentile range of each scenario in b and e and the 90th percentile range in c and f.

The charts show that, for every five-year delay in reaching peak emissions (upper charts), temperatures rise higher (middle charts), which causes more sea level rise in the long run (lower charts).

Expected CO2 emissions, temperature rise and sea level rise for a net-zero CO2 emissions scenario (a-c) and a net-zero GHG emissions scenario (d-f). Coloured lines and symbols are used to indicate simulations at five-year intervals from 2020 to 2035. Grey lines show simulations exceeding 2C. Shading shows the 66th percentile range of each scenario in b and e and the 90th percentile range in c and f. Source: Mengel et al. (2018)

Glossary

RCP8.5: The RCPs (Representative Concentration Pathways) are scenarios of future concentrations of greenhouse gases and other forcings. RCP8.5 is a scenario of “comparatively high greenhouse gas emissions“ brought about by rapid population growth, high energy demand, fossil fuel dominance and an absence of climate change policies. This “business as usual” scenario is the highest of the four RCPs and sees atmospheric CO2 rise to around 935ppm by 2100, equivalent to 1,370ppm once other forcings are included (in CO2e). The likely range of global temperatures by 2100 for RCP8.5 is 4.0-6.1C above pre-industrial levels.

RCP8.5: The RCPs (Representative Concentration Pathways) are scenarios of future concentrations of greenhouse gases and other forcings. RCP8.5 is a scenario of “comparatively high greenhouse gas emissions“ brought about by rapid population growth,… Read More

The results suggest that sea levels could rise by 70-120cm by 2300 under a low emissions scenario. This level of sea rise could significantly increase the risk of flooding in coastal cities, such as New York, and island atoll nations. Currently, global emissions are tracking a higher scenario known as RCP8.5.

The results also indicate that, even once net-zero emissions are achieved and temperatures begin in fall, sea levels will continue to rise. This is because the drivers of sea level rise respond slowly to climate change, Mengel says:

“There are also unstable processes that, once triggered, will not stop contributing to sea level rise, independent of global mean temperature rise. An example of this could be the potential collapse of the West Antarctic ice sheet.”

Peak urgency

The findings show that the world must “reduce its emissions as fast as possible” in order to protect future generations from extreme sea level rise, Mengel says:

“Peaking global CO2 emissions as soon as possible is crucial for limiting the risks of sea level rise, even if global warming is limited to well below 2C.”

The results could hold relevance for today’s large infrastructure projects, which typically have a lifespan of more than 100 years, says Dr Natasha Barlow, a university research fellow specialising in sea level change from the University of Leeds, who was not involved in the research. She tells Carbon Brief:

“As a result, there is huge value in studies which consider the rate and magnitude of sea level rise beyond 2100. There are very few studies which do, largely as the uncertainties increase the further into the future we try to predict.”

However, the models used in the study do not include all of the “low probability, high risk” drivers that may contribute to sea level rise, she adds:

“There may be additional long term sea level rise from melting ice, above that predicted by the authors, due to marine ice-sheet instability driven by warmer ocean waters around West Antarctica and an albedo feedback over Greenland.”

The post Every five-year delay in meeting Paris goals could ‘add 20cm’ to global sea levels appeared first on Carbon Brief.

Guest post: How ‘enhanced weathering’ could slow climate change and boost crop yields

Prof David Beerling, director of the Leverhulme Centre for Climate Change Mitigation, and Prof Stephen Long from the Department of Crop Sciences and Plant Biology at the University of Illinois at Urbana–Champaign.

Achieving the Paris Agreement goals of keeping global warming to “well below” 2C, or to 1.5C, above pre-industrial levels will require rapid decarbonisation of human society.

But national commitments to rein in greenhouse gas emissions are currently insufficient to meet these agreed limits. It is increasingly likely that “negative emissions”, or “carbon dioxide removal”, technologies will be needed to take up the slack.

These techniques involve extracting CO2 from the atmosphere and storing it indefinitely. Scientists have proposed a range of different approaches and we now need realistic assessment of these strategies, what they might be able to deliver, and what the challenges are.

In a new paper for Nature Plants, we tackle an under-discussed technique of CO2 removal called “enhanced rock weathering”. Our research highlights the potential wider benefits for crop yields and soil health, and sets out a research agenda for the next steps.

What is enhanced weathering?

As you might remember from geography classes at school, chemical weathering is a natural process that continuously erodes away rocks in our landscapes and sequesters atmospheric CO2 over millions of years.

The process begins with rain, which is usually slightly acidic having absorbed CO2 from the atmosphere on its journey to the ground. The acidic rain reacts with the rocks and soils it lands on, gradually breaking them down into minute rock grains and forming bicarbonate in the process. Eventually, this bicarbonate washes into the oceans, where the carbon is stored in dissolve form for hundreds of thousands of years or locked up on the sea floor.

Enhanced weathering scales up this process. It involves pulverising silicate rocks such as basalt – left over from ancient volcanic eruptions – to bypass the slow weathering action. The resulting powder, with a high reactive surface area, is then spread on large areas of agricultural land where plant roots and microbes in the soil speed up the chemical reactions.

As natural rock weathering absorbs around 3% of global fossil fuel emissions, enhanced weathering can provide a boost to remove even more CO2 from our atmosphere.

But the potential benefits do not end there. As enhanced weathering makes water more alkaline, it can help counteract ocean acidification.

And adding minerals to soils can boost nutrient levels, improving crop yields and helping restore degraded agricultural soils.

Food demand

The need to cut CO2 emissions is unfolding alongside an unprecedented increase in food demand – linked to dietary changes and a growing population that may surpass 11 billion by 2100 (pdf). At the same time, farming itself a growing contributor to climate change.

Critically, enhanced rock weathering works together with existing managed croplands.  Unlike other negative emissions techniques under consideration, it doesn’t compete for land used to grow food or increase the demand for freshwater.

While enhanced weathering can be applied to any soils, arable land is the most obvious candidate as it is worked and planted throughout the year. It covers some 12m square kilometres – 11% of the global land area.

In fact, arable farms already apply crushed rock in the form of limestone to reverse acidification of soils caused by farming practices, such as the use of fertilisers. And there is a long history of small-scale farming using silicate rocks to improve crop yields in highly-weathered soils in Africa, Brazil and Malaysia.

Swapping silicate for limestone, and increasing the application rate, would do the same job to help tackle acidification, but help capture CO2 from the atmosphere at the same time.

Managed cropland, therefore, has the logistical infrastructure, such as road networks, and the machinery needed to undertake this approach at scale. These considerations could make enhanced weathering potentially straightforward to adopt.

You can see this in action in the video below from the Leverhulme Centre for Climate Change Mitigation.

Using silicate rocks as a resource in this way could also have a number of important wider benefits. These include supplying silica back into soils to improve crop health and protection from pests and diseases, and supplying nutrients to increase yields.

If realised, these benefits would reduce the usage of agricultural fertilisers and pesticides, lowering the cost of food production, increasing the profitability of farms and reducing the barriers to take up enhanced weathering for the agricultural sector.

Estimates and challenges

So, in theory, there are a lot of potential upsides for using enhanced weathering. However, like many negative emissions technologies, implementation is still in its very early stages. It needs further research, development and demonstration – not just across a range of crops and soil types, but also different climates and spatial scales.

There have been some successful field tests of using enhanced weathering – though for purposes other than capturing CO2.

For example, in a 12-year study conducted in a New Hampshire forest, scientists measured the effect of spreading silicate powder as a method of accelerating recovery from acid rain. The results confirmed some of the main impacts of enhanced weathering – a rapid increase in dissolved silicate and calcium making it into streams, and alleviation of acidification in the ecosystem.

Similarly, in Mauritius, sugarcane trials as far back as 1961 added crushed basalt to soils and increased yields by 30% over five successive harvests.

There are other challenges too. The process of mining, grinding and spreading rocks on a large-scale would likely have negative environmental and ecological impacts, and would therefore require careful management. Depending on the size of the grains of powder the rocks are pulverized down to, the energy demand could account for 10-30% of the amount of CO2 sequestered. Using renewable energy sources would minimise this.

Costs, too, need to be considered. Current cost estimates are uncertain and vary widely. The most detailed analysis to date puts operational costs at $52-480 per tonne of CO2 sequestered – though these estimates are poorly constrained and improvements in crop yields and lower fertiliser needs will offset some of these costs. This compares with a $39-100 per tonne of CO2 for another, more talked-about negative emissions technology, bioenergy with carbon capture and storage (BECCS).

Credit: Dr Ilsa Kantola, University of Illinois, Champaign-Urbana

But the potential is significant. For example, applying 50 tonnes of basalt powder per hectare per year to 70m hectares of the corn belt of North America might sequester as much as 1.1bn tonnes of CO2 in the long run – equivalent to 13% of the global annual emissions from agriculture.

Countries with considerable productive farmland have the largest potential to sequester CO2 through enhanced weathering. These include the US, China, India and Russia, which all grow crops on a massive scale and make up the highest emitters of CO2.

Scaling estimates up to a global level is tricky, but – for example – adding 10-30 tonnes of silicate per hectare per year to two-thirds of the world’s most productive cropland could take 0.5-4bn tonnes of CO2 out of the atmosphere per year by 2100. But current estimates are highly uncertain and require more research.

Putting theory into practise

Human societies have long known that volcanic plains are fertile; ideal places for growing crops without adverse human health effects but, of course, with little consideration for how adding additional rocks to soils might capture carbon.

We now need to take the theory and laboratory tests out into real crop fields to see how enhanced weathering fits – practically and economically – in the wider portfolio of options for removing CO2 from the atmosphere.

However, there is still a long way to go and research in this area remains in its infancy.  Improved assessments are required to understand how much CO2 the approach would capture, how much rock is required, how much energy is required to crush and distribute the rock, and to better understand the long-term effects on soils and water courses.

We need to undertake carefully monitored assessments on arable land. For example, can we demonstrate the expected benefits to crops amidst the seasonal and annual variations in the weather?

And finally, we need to better understand the public perception of enhanced rock weathering as a strategy for carbon capture, communicate the process, benefits and risks, and understand any public concerns about what this means for our landscapes and farmlands.

The post Guest post: How ‘enhanced weathering’ could slow climate change and boost crop yields appeared first on Carbon Brief.

Oh dear, a virus ‘jumps’ from plants to bees

The bane of the bee is varroa. We warn new beekeepers that varroa will kill their bees faster than they can say “varroosis five times.  Varroa kills. Thirty years ago, the mites weren’t as bad as they are now. In those days, they sucked a bit of bee innards, slowly weakening and killing the bees. But over the years, peripatetic mites began to carry viruses from bee to bee. Some researchers suggest that varroa’s viral accomplices cause more damage than the mites themselves. Because of the attached viruses, the effect of varroa is more harmful than it used to be. And the problem may get worse with time as mites encounter new viruses and spread them.

Tobacco leaf with ringspot virus

A new viral culprit was recently identified by researchers at the USDA and the Chinese Academy of Sciences.  Tobacco ringspot virus is incredibly nasty but was thought to just injure plants, not animals. Ringspot almost wiped out the tobacco business (must try harder next time) and causes such grief that farmers may abandon infected crops, plowing them under, and returning only years later when they hope the virus population is low and won’t be a problem for a while. Despite the name, the tobacco virus also affects dozens of different sorts of plants. Now, it seems, it can hurt animals, too. This is new to me – until now, I never heard of a virus jumping from plants to animals. Avian flu jumped to humans and HIV came to humans from chimps – but I didn’t know that a plant virus could hurt some animals.

Normally, a plant virus is benign to insects. Plant and animal cell structure is fundamentally different. Injury shouldn’t occur, but viruses ride in pollen and travel from plant to plant, spreading plant infections like uncovered coughs. In the case of honey bees, the virus is picked up in pollen and brought to the hive where it’s ingested. It’s not uncommon to find a variety of viruses in bee guts and saliva. Typically, the virus does no harm to the insect carrier. It hangs out in the bee, then gets excreted onto some unlucky plant during a bee’s cleansing flight. Liberated, the virus attaches to a new host plant and starts making ringspots again.

In the journal mBio, American and Chinese scientists reported that tobacco ringspot virus affects bee guts – and wings, antennae, blood and all other body parts of bees. The virus is believed to shorten a bee’s life. The virus travels when a varroa mite sucks out the innards of honey bees. As a mite passes from bee to bee, she (phoretic varroa mites are girls) injects victims with the virus as she eats.

You can read the entire paper online, but here’s part of the abstract from “Systemic Spread and Propagation of a Plant-Pathogenic Virus in European Honeybees, Apis mellifera”:

“…In the present study, we showed that a plant-pathogenic RNA virus, tobacco ringspot virus (TRSV), could replicate and produce virions in honeybees, Apis mellifera, resulting in infections that were found throughout the entire body. Additionally, we showed that TRSV-infected individuals were continually present in some monitored colonies. While intracellular life cycle, species-level genetic variation, and pathogenesis of the virus in honeybee hosts remain to be determined, the increasing prevalence of TRSV in conjunction with other bee viruses from spring toward winter in infected colonies was associated with gradual decline of host populations and winter colony collapse, suggesting the negative impact of the virus on colony survival. Furthermore, we showed that TRSV was also found in ectoparasitic Varroa mites that feed on bee hemolymph, but in those instances the virus was restricted to the gastric cecum of Varroa mites, suggesting that Varroa mites may facilitate the spread of TRSV in bees but do not experience systemic invasion.”

From the abstract, above, you’ll note that varroa mites spread the virus but the mites don’t “experience systemic invasion.” Wouldn’t it be great if it were the other way round – a virus carried by bees that doesn’t hurt bees, but kills mites?  I’ll bet someone is working on that right now.

Spreading a virus?

The idea that a plant virus can spread within an animal is an uncomfortable surprise. It reminds us of the original movement of varroa itself from Apis cerana, where it didn’t cause much mischief, to Apis mellifera, where it is devastating. Once again, we have a pest jumping species (actually, in this case, jumping from the plant kingdom to the animal kingdom).

Ringspot now gets added to the growing list of other viruses spread by varroa mites: deformed wing virus, acute bee paralysis virus, varroa destructor virus-1,  the Israeli acute bee paralysis virus and the Kashmir bee virus. The novelty with the tobacco virus is that it shouldn’t reproduce inside honey bees and hurt them, but it does.

What’s this got to do with you and me? Well, two things. If you give up smoking, there will be fewer tobacco plants and that means fewer ringspot viruses and that means healthier bees. (And a healthier you.)

Secondly, if the big problem is unpredictable new mite-carried viruses, control of mites becomes more and more urgent.  The ‘new’ virus warns us that unexpected varieties of these tiny creatures will continue to invade bees and make them sick. We can’t anticipate what sort of virus will be next nor can we create inoculants. (Heck, we can’t even tame the virus that causes human colds.)  So, be prepared – this problem is going viral.

How do you prepare to fight viruses? Rest, drink lots of fluids (chicken soup!), stay warm, and reduce stress. On a deeper level, white blood cells and the hormone interferon help you fight viruses. Similarly, honey bee colonies may shake off some viral infections if the bees are otherwise healthy, have prolific queens (the source of healthy young replacement bees), plenty of nutritious pollen, and strong populations. Spring can be a particularly vulnerable time – bee population is low, queens are aging, fresh pollen is scarce.  Life-cycle stresses weaken the hive. You want strong hives. Strong colonies are more resistant to afflictions of all sorts.

Do everything you can to keep healthy colonies and kill those blasted virus-toting mites. You’ll give your bees a good chance to survive the spring and grow into honey-making hives.

There was a time when tobacco and bees mixed freely.
This is from a 1950s Virginia tobacco festival parade.