My Climate Change Garden

Climate change has serious implications for bees.An article by Mark Patterson, Forage Officer at the London Beekeepers Association explains how extreme weather can affect their survival.

What is climate change and what are the issues around it?

To understand how climate change will potentially affect our pollinators we first must ask ‘what is climate change?’  Simply put it can be described s a ‘significant and lasting change in the statistical distribution of weather patterns over periods ranging from decades to millions of years. It may be a change in average weather conditions, or in the distribution of weather around the average conditions (i.e., more or fewer extreme weather events).’ Basically it means our regular weather patterns will become more chaotic, unpredictable and frequency of extreme weather events such as the flooding’s of 2013/2014 will in all likelihood become more common.

For many years the term climate change was rarely used and the phrase ‘Global Warming’ was spoken about more frequently. Whilst the two terms are connected they have very different meanings. Global warming refers merely to the increase in mean earth temperatures which are contributing to polar ice retreat. Climate change on the other hand describes changes in much more detail beyond simplistic warming of temperatures. Climate change is influenced greatly by global warming so global warming is a part of climate change and in part responsible for changes in our weather patterns but the term Global Warming can be misleading as not all parts of the Earth will actually become warmer nor will the Earth warm evenly. In the short term the earth may warm up by several degrees but through climate change many areas may actually become much cooler so the term ‘global warming’ is now used much less as it is not such an accurate description of what is happening. It is worth pointing out that climate change is nothing new to the Earth. It has been happening ever since the Earth was formed and occurs naturally as a result of changes in solar activity, tectonic and volcanic activity, changes to the distribution of Plant biomass covering the earth and even cosmic events such as meteorite impacts.

The current concern about climate change and what is happening right now is that it appears to be happening at an alarming rate as a result of mans impact on the Earth, our interference with the planets natural carbon cycle through burning of fossil fuels and destruction of global plant cover. Many scientists are alarmed that the speed of change could mean many species of plants and animal will be unable to adapt quickly enough and this could lead to more and more species becoming extinct as well as putting increased pressure on world food production.

To understand how climate change may affect us here in Britain we need to understand how it will influence our weather system. Two constant and critically important natural phenomena help regulate our climate here in the UK, and both are effected by rising mean global temperatures. Firstly the Atlantic Conveyor, a section of the worlds oceanic currant may be affected. The Atlantic Conveyor influences the UK climate by picking up warm waters from the Tropical Latitudes and depositing that warm water off our western shores. At the same time the conveyor collects cool nutrient rich water from the north Atlantic and then folds back on itself carrying them to the warmer latitudes of the south where the conveyor continues passing around the globe eventually coming full circle. Scientists studying the worlds Climate and Ocean’s think that the Atlantic conveyor is responsible for regulating our climate here in North Western Europe and that without the benefits of the conveyor our average temperatures would be 4 degrees cooler in summer and far colder in winter.

One popular climate change theory predicts that increased flow of fresh water into the north Atlantic caused by polar ice melting could push the conveyor further south so the UK would miss out on the conveyors warming influence and our climate would become much cooler. In this instance we could expect to experience Alaskan style winters with increased snow fall and mean winter temperatures rarely rising above 0 Celsius. The conveyor instead could take its warm water to the Mediterranean and North Africa which could see temperatures in that region rise significantly leading to a spread in desertification. This would spell disaster for many plants and animals including ourselves, Honey Bees and wild pollinators. The other phenomenon which scientists are worried may be effected by Rising temperatures is the Jet Stream.  A powerful, persistent, high-altitude “river of air” which circumnavigates around the world between 100-200mph from west to east, affecting the weather as it goes. Occurring around 11km above the planet surface the jet stream is made up of 2 air currents the polar jet and the subtropical jet. It is the polar jet which influences our climate here in the UK the most. The polar stream is fuelled by differences in temperature and humidity between the warm middle latitudes and the cooler latitudes of the north.  The position or exact latitude of the Jet dictates how its air stream affects our weather patterns. Normally the Jet is positioned at latitudes above that of the UK which means cool turbulent weather fronts carried by it are send north east of us out of harms way. When the jet shifts position to lower latitudes it can result in wet weather hitting our shores from fronts coming off the Atlantic. Fortunately this does not happen very frequently.

A recent and popular Theory by US scientist Jennifer Francis, at Rutgers University claims that as global temperatures rise, the difference in mean temperature between the higher and lower latitudes is decreasing and slowing down the jet stream. So instead of a fast torrent of air pushing adverse weather north-east to wards the Arctic and out of harms way the jet stream begins to slow down, oscillate and meander. As the stream thrashes about it throws out extreme weather patterns in all directions rather than sending them north of us. This theory is widely considered to be what happened in 2013 when much of the north East USA was hit by severe tropical storms followed by an arctic like winter and northwest Europe experienced the wettest winter in living memory.   Changes to either or both of these weather influencing systems could lead to increased unpredictability in the UK climate. As a result we could expect to see short to mid term rises in average temperatures, increased incidences of extreme wet weather, increased instances in sudden cold weather, more frequent high intensity storms and frequent and sudden heat waves in Summer.

It is also likely that we will see significant changes to timings of the seasons. According to research undertaken at Reading University evidence already suggests that on average plants are flowering 4-7 days earlier every 10 years than they have done in the past.

How will bees be affected by these changes?

This is worrying for many of our pollinators which rely on the availability of specific flowers upon emergence from hibernation in spring. At the same time we are noticing our plants emerging earlier and earlier evidence is suggesting that our bees are actually emerging from hibernation twice as early as our plants are. For some species seasonal change could mean the difference between life and death.

Imagine you are a bumble bee Queen of one of our more vulnerable species emerging in spring. You are heavily reliant on the presence of clover and other legumes whose pollen is a rich source of protein you desperately need to bring your body back into breeding condition after your 9 months in hibernation. You awake in a state of near starvation and find the flowers have not emerged when you were expecting them to. You could have a long wait until you are able to feed and depending upon how well you were able to feed up prior to your long hibernation you may not survive to see those flowers emerge. Repeat this scenario over consecutive years and some already vulnerable species could be pushed to the brink of extinction.

Species most at risk from climate change are those with already limited distributions, extreme north or southern ranges, those relying on habitats just above sea level (such as our recently re-introduced Short Haired Bumble Bee) and species with very specific habitat and flower requirements. Thermogenic (warmth loving) species could also be affected by a changing climate.

There are many species in the UK which can be placed into one or more of the above mentioned at risk categories. An increase in freak weather events such as wide spread flooding also has the potential to badly affect many species of bumble and solitary bees. Most of these species nest and hibernate under ground so are particularly at risk from flood events. If their nests are not washed out and the bees drown then nesting in damp conditions can increase the likelihood of fungal pathogens like Chalkbrood leading to an increase in mortality among the bees pupa. Habitat’s moving as a result of climate change is another real threat. Many plants and the animals which depend upon them have specific temperature and humidity ranges outside of which they struggle to survive.

As our climate changes we may see plant species  and habitats re-distribute themselves to enable them to survive as previously favourable conditions disappear and new ones emerge elsewhere. Many species will have difficulty in achieving this as man has heavily engineered the landscape and urban sprawl and intensive agriculture separates natural areas preventing free movements of species. It is therefore vital that existing habitats and migratory corridors are strengthened to facilitate movements of species. We need more investment in landscape approaches to conservation such as those of the Buglife River of Flowers project. http://www.riverofflowers.org/

Climate change could also have consequences for migratory species of pollinator. Many will be surprised to know that tens of millions of insects migrate to our shores each summer from Tropical  Africa and the Mediterranean. Two such species are the Painted Lady Butterfly and the Hornet Hoverfly. Both these insects perform annual migrations equally if not more impressive as those of the famous American Monarch Butterfly. In spring adult Butterflies and Hoverfly migrate north to the UK where they reproduce and die. Their offspring emerge in late summer and before the onset of autumn make the epic 9000 mile return journey south. Whilst strong flyers, these species need still calm conditions to cross the English Channel.Upon their return journey in autumn the Painted lady flies at altitudes of up to 1000 meters and travel at speeds up to 30 miles per hour on favourable winds which take them south. In 2009 26million were tracked by radar at high altitude making the return journey south over British skies. Changes in weather patterns could mean migratory species like these 2 insects struggle to reach our shores on an annual basis and may become extinct as regular breeding species in the UK. Neither species can survive our cold wet winters.

How will the weather affect honey bees?

Any one who keeps honey bees will know that the weather and your honey yields go hand in hand. Honey bees will not fly in cold or wet conditions so an increase in torrential rain events like those experienced during the spring and summer of 2012 would be disastrous for honey bees. 2012 saw some of the worst honey harvests on record with average honey yields down 71%. This was a result of the bees inability to fly during the heavy downpours. When there was a break in the rain, there was little pollen or nectar left on our flowering plants for the bees to feed on as much of it had been washed off by the rains. For the first time in my beekeeping experience I had to feed colonies all the way through spring up until July to avoid starvation.   Our apple farmers suffered heavy crop losses as a result of poor pollination that year which resulted in apple prices souring in the supermarkets and a decrease in variety on the shelves. Other consequences that year for our Honey Bees did not become fully apparent until the following spring. Our Queens need still calm conditions in which to conduct their mating flights. As a result of the very wet summer of 2012 many young Queens were poorly mated and many keepers lost colonies early the following year as their queens fertility ran out. This situation was made worse by the harsh winter and late arrival of spring in 2013 which also saw an increase in cases of Nosema (a fungal pathogen) in many colonies.

Of all the bee species on Earth the Honey bee is the most robust, adaptable  and probably the most  genetically diverse. With around 40 races of Apis mellifera globally there are strains of Honey bee suited to almost every climatic condition. We may find that as a consequence of climate change some races of honey bee will become less well suited to particular climates and other strains of bee may need to be brought in to fulfil our needs as beekeepers. This would help ensure to a certain degree that pollination services continue to be fulfilled and our honey producing industry does not die out.

Some species may benefit from a warming climate

As with all changes some species will suffer with the consequences but some may also benefit. One species which may benefit from rising temperatures as a result of climate change in the UK is the Violet Carpenter Bee. This large metallic blue bee favours hot conditions and is commonly found throughout North Africa and the Mediterranean. In recent years it has been pushing northwards into other areas of Europe and as recently as 2007 has been recorded in southern England. It has been recorded most years since but it is not yet known if the population is sustainable. If temperatures continue to warm we could see a full colonisation effort from this species similar in nature to that of the Tree Bumble Bee which has also recently conquered the UK. This particular bee nests and hibernates above ground in hollow plant stems so is less vulnerable to flood events.                                            

What needs to be done to protect our pollinators from climate change?

It is down to our world leaders to address climate change reversal and take steps to slow down climate change – if it is at all possible. Scientists are suggesting that the damage is already done and global temperatures in the short term (30-50 years) are likely to continue to increase even if measures are put in place now to reduce greenhouse gas emissions.  On a more practical level we can all help pollinators cope with changes to our climate by reducing stresses already placed upon them by man.

• We need to reduce our dependence on agricultural pesticides which are affecting our pollinators.
• We must deal with exotic pests and diseases which are crippling our honey bees and bumble bees
• We must invest in more habitat creation which will link existing habitats and allow species freedom to migrate as habitats change with our climate.
• We need to look at alternative crops and garden plants that will cope well with predicted changing conditions to ensure our nations food security and that our pollinators still have plants to feed on.
• We need to look at more sustainable methods of design and construction in our urban centres to tackle excessive rain water run off, water storage and urban heating.
• No one knows with any certainty how our climate will change or what the impacts will be on our pollinators as the science exploring the potential outcomes is still in its infancy and much remains unknown about the exact biology of many of our pollinators.
• What is clear is that climate change has the potential to have lasting effects on our pollinators and food security and we need to do everything we can to reduce existing pressures on pollinators if they are to cope with a changing climate.
• Explore the London Beekeepers Association website for further information about the importance of bees http://www.lbka.org.uk/