Looking to the future

Looking to the future: The changing climate will have a big impact on the way we garden. We’re investigating ways in which we can manage these changes

Gardens can come in many forms, from a single container  to a large domestic garden. They can be school, hospital or community gardens, or managed  areas open to the public, such as components of urban parks, the grounds of stately homes or botanical gardens. They are multifunctional spaces, important for health and social well–

A summary of climate projections

• Global mean surface temperature has increased by 0.86°C from

1880 to 2016 and is projected to continue to rise.

• The rate of future increase is dependent on the extent to which

7. Even if greenhouse gas emissions are reduced today, the climate will continue to change rapidly over the coming decades due to historic emissions. Consequently, gardeners should be mindful that trees planted now might not be suited to the climate in

2050, for example.

being whilst also supporting the natural environment by helping to

CO  and  other  greenhouse  gas  emissions are  restricted  in

sustain wildlife. Gardens also provide important ecosystem services,

such as mitigating urban flooding, urban cooling, building insulation, pollutant capture and carbon sequestration.

forthcoming years.

• Even  with stricter legislation on  greenhouse  gas  emissions, global temperature  may still rise by at least a further 1.5 to

What can you do?

1. Green your living  space.  Trees and  plants  remove heat–

Since  the  2002   publication  of  the  ‘Gardening  in  the  Global 2.0ºC over the next 100 years. Average temperature is projected trapping CO from the atmosphere, reduce the risk of flooding,

Greenhouse’ report, the climate has undergone  dramatic change, with 2016 proving to be the warmest year on record (Met Office

2017; NASA 2017). The global climate is changing rapidly as a result of greenhouse gas emissions, and we are already experiencing the consequences of this, including more frequent and intense rainfall events in combination with rising temperatures. These changes will be compounded  if human  activities continue to emit carbon and other polluting compounds at the current rate. Despite this, there is a relentless trend to replace green space with impermeable surfaces, and  burn fossil fuels to the  extent  where atmospheric pollutants are  frequently  reaching  toxic concentrations  in our increasingly urbanised world.

With populations rising and housing development set to continue into the  future, the  role of gardens  in delivering the  health  and environmental ecosystem services formerly fulfilled by the natural environment will become increasingly important. With over half of UK adults engaged in gardening (Department for Culture Media and Sport 2015), there is great potential for this group to help maintain biodiversity, make a major contribution to reducing carbon dioxide emissions and prepare for the growing impacts of climate change.

In 2012, Defra released their first Climate Change Risk Assessment report,  which was  reviewed  in  2017.  The  most  recent  report identified invasive organisms (including pests, diseases and invasive non–native  species), resource use and  soil health  as key risks of climate change  and  highlighted the  need  for further research in these areas (Defra 2017). These risks align with those found by this report to be particularly relevant to gardeners, and are fundamental in underpinning scientific research at the RHS.

Gardens are important for many aspects of society, and their ubiquity means that they should be considered by policymakers, governments and NGOs who seek to mitigate the impacts of climate change and encourage adaptation at a national scale. This report has:

• Explored evidence  that  currently exists with regard  to  the intrinsic link between gardens and climate change.
• Summarised the implications of climate projections for gardeners.
• Outlined ways in which gardeners can both adapt to a changing climate, but also mitigate against further greenhouse gas emissions.

to increase in all seasons and across all regions of the UK.

• There will continue to be high year on year variability in rainfall.
• It is likely that  there will be an increase in the number of dry spells, and this will be most pronounced in southern areas of the UK, and especially over the summer months.
• The frequency of very wet days will increase over the winter, and this will be most pronounced in northern areas of the UK
• Gardens  close to  the  coast  or located  near  estuaries  may experience more flooding as a  result of an  increase in the frequency and severity of tidal surges, whereas gardens located upstream will experience an increase in flooding due to more frequent and intense fluvial flooding events.

• It is theoretically possible that  in the future, much of the UK

could be frost free in some years.

Implications for gardeners

1. Warmer springs and autumns will extend the growing season and, therefore, some species will flower earlier and some will experience delayed leaf colouring or leaf fall. There will also be the need for more weeding, mowing and pruning.

2. A longer growing season  might allow for a wider variety of plant species to be grown. When attempting to grow different varieties, gardeners will face a continual trade–off between a longer growing season and extreme weather events.

3. The amount of solar radiation available for plant growth has increased by around 5% relative to 1961–1990. This has been linked to a reduction in cloud cover.

4. Extreme rainfall events might increase the rate that nutrients, particularly nitrogen are washed out of the soil. Therefore, the timing of fertiliser application should be carefully considered.

5. Dry spells are  projected   to  occur  more  often;  therefore gardeners will need  to consider methods  of capturing water during intense rainfall events.

6. It is expected that  warmer conditions will favour the spread of existing pests and diseases, in addition to aiding the establishment  of  new  cases.  However, climate  change  will mean that populations of those pests and diseases who exploit frost wounds, for example, may struggle to survive.

and some species can even capture particulate pollution.

2. Plant a  diverse  range  of  plants  in your garden.  Earlier flowering might disrupt host–pollinator associations, so plant a  diverse variety of pollinator friendly plants  with different flowering times.

3. Adopt new ways of growing. Green roofs and walls can result in year–round home energy savings due to a cooling effect in summer and an  insulating effect  in winter. Improve energy efficiency through use of technologies and try to reduce the use of petrol–powered tools.

4. Water use and management in gardens. Seek water butts with a larger than standard capacity to ensure a sufficient water supply over the summer. Select plants and design strategies better suited to the environment.

5. Avoid peat. Peatlands store considerable amounts of carbon.

Look, ask for and use peat–free composts. There are now some high quality products out there that work.

6. Compost your garden and kitchen waste. Gardeners may wish to  compost  more  garden  and  kitchen waste  as  this provides excellent nutrients for the garden, but thrown away as household waste, it ends up on landfill and produces potent greenhouse gases.

7. Adopt the 4R’s. Reduce – the use of resources in your garden wherever possible, Reuse – household materials and seasonal items year on year, Recycle – your garden waste, plastic, glass and metals and Reinvest – help stimulate demand for recycled products by buying recycled items.

8. Avoid wherever possible  the  use  of  chemicals  in  your garden. As a first choice avoid the  use of chemicals in the garden. If required, use products with a low carbon footprint.

9. Practice Integrated   Pest  management  (IPm). Adopt  a combination of good plant biosecurity, biological, cultural and chemical controls in order to minimise the spread of pests and diseases.

10. Invasive Species. Gardeners should ensure that their cultivated plants remain in the garden, and that legislation is adhered to during plant disposal.

Source: https://www.rhs.org.uk/

Article Link: https://www.rhs.org.uk/science/gardening-in-a-changing-world/climate-change