Climate Change and Plant Growth
In our own back yards we often see the warming climate as a benefit to our gardens, especially in the North and Midwest. Our plants have a longer growing season and there are more plants that will survive our cold winters. But it’s time to better understand what is really happening to our plants as climate rapidly changes worldwide.
In reality, the length of growing season could decline and the plants we know and love may no longer grow at all. Extreme temperature fluctuations are becoming the new normal, and plants are quite easily affected by changes and extremes, and do not have the same ability to adapt and move that animals have. So it is important to understand what is happening to plants and what can be expected as our climate continues to change.
The benefits of climate change as it affects plants can already be seen. In the North and Midwest warmer temperatures, earlier spring and later fall frosts give plants a longer growing season. Although in high altitudes spring and fall are both coming later, and in the warm Southeast the growing season has gotten shorter. Crop yields can increase, foliage grows longer and stronger, flowers bloom more profusely and for longer periods.
Interestingly, more carbon in the air from greenhouse gases also benefits plants. Increased CO2 in the air stimulates plant growth and crop yields. Photosynthesis and moisture use become more efficient in some plants, which also increases growth. Foliage and root growth is improved.
Some of these benefits can be quite quickly negated by extreme weather conditions caused by climate change. Unusually and unexpected late frosts and freezes can quickly damage budding plants or kill plants that until recently were too tender to consider growing. Extreme and prolonged freezes can kill plant roots that would normally be protected deep in the soil. Regions across the globe are experience severe drought, extreme flooding, fires and storms. Needless to say, this is wreaking havoc not only for humans and animals, but of course plants and crops.
Specific Adverse Effects of Climate Change to Plants:
Changing flowering times may eventually be out of sync with the presence of pollinators.
Drought and heat retards the growth of plants.
With rising temperatures plants will grow tall and more spindly to keep cool, creating a weaker unstable plant.
Extreme heat or cold will push some plants beyond their limits of survival.
Altered patterns of rain resulting in drought and flooding will change the moisture availability and negatively impact plant growth.
Changing rainfall also changes soil, leaving some species unable to thrive.
As plant species fail, invasive species are better able to take over.
Plants require fairly specific environmental conditions to complete they life cycles, including reproducing.
Plant species that are able have already begun shifting their growing region to higher altitudes or cooler regions. Species unable to adapt or shift their range to more suitable climate will eventually cease to exist.
The inability of plant species to adapt, shift, or compete with other plants will lead to reduced diversification. Diversity is key to the evolution of an ecosystem.
Symbiotic relationships within ecosystems could change if a plant shifts into new regions, as well as relationships with parasites and pathogens.
Bird migrations are already changing, which can begin to affect pollination of ecosystems they are leaving earlier and arriving later.
Increasing CO2 in the air is leading to increased carbon retained in plants, altering the nitrogen ratio in foliage. This may affect the nutrition of herbivorous creatures.
Examples of Specific Plants and Crops Adversely Affected by Climate Change:
Increasing heat may affect vernalisation of wheat and sterility in rice.
Corn requires frequent rain. Long dry periods followed by long rain periods, in addition to increased heat will substantially reduce yields throughout the Midwest.
Wheat yields will likely suffer substantially.
Extreme heat during flowering affects crop development.
Tree species have already begun to migrate to more favorable conditions.
Invasive plant species have already expanded their ranges.
Orchids bloom at a very specific time coordinated between the awakening of male and female bees. Females are awakening earlier, reducing the time to pollinate orchids.
Fruit trees often require a winter chill to bloom and produce fruit. Through the southeast and western central valleys much of that chilling may be lost.
Some crop yields are increased by CO2 increases but increased temperatures negates the effect.
Crops grown in the temperate mountainsides of the tropics may see more temperature fluctuations, making it difficult for coffee crops.
California fruits and nuts depend on the snow melts from the mountains. With warmer winters the snow will be replaced by rain, failing to supply necessary spring water.
Changes in plant growth and migration of species to more favorable conditions can dramatically change habitats for a number of species. If we do nothing to mitigate climate change, plant growth can be expected to be stunted. Although cold regions globally will gain growing days, weather extremes could eliminate any benefits. Tropical regions will lose substantial growing days, enough to not only affect the ability of poor country’s populations to thrive, but will also affect global food supplies.
We must each do everything we can to contribute to improving the environment. What we are able to do may not be a direct benefit to plant life, but if it is helpful to reducing global warming it certainly will benefit our plants.