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
- 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.
- 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?
- 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
- 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.
- 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.
- 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.
- 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.
- Dry spells are projected to occur more often; therefore gardeners will need to consider methods of capturing water during intense rainfall events.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- Invasive Species. Gardeners should ensure that their cultivated plants remain in the garden, and that legislation is adhered to during plant disposal.
Article Link: https://www.rhs.org.uk/science/gardening-in-a-changing-world/climate-change