Climate change is one of the most significant challenges facing us all. Weather and gardening are inseparably linked and successful gardening requires stable, predictable weather.

It’s the relative stability of our climate that makes weather forecasting so reliable. The signs of climate change are all around us. If you’ve been gardening for more than a few years, you’ve noticed that the seasons are increasingly more unpredictable. Gardeners are particularly in tune with nature, but who hasn’t observed how abruptly the seasons change with little or no transition. Flowers and trees start blooming earlier and frost dates vary widely from year to year.

The changeability of Kansas weather has always been the norm, but changes over the past several decades have defied historical trends. Over the past 100 years, the number of frost-free days have increased significantly. During the past decade, temperatures in Kansas have been the warmest on record except for the Dust Bowl era of the 1930s. At first, a longer growing season might seem like a good thing, but not necessarily. There will be subsequent increases in pressure from weeds, insects and diseases. Organic gardeners will face significant new challenges. Hotter, drier summers will dramatically change the way we garden. Our climate is in a state of flux. Are our actions responsible for it? Cleary, the answer is yes. How do we know this to be true?  

The history of the Earth’s climate reveals itself in many ways. Trees are some of the oldest living things on Earth. Tree rings are formed by the changes in a tree’s growth over the course of a year. They tell us how old the tree is and what the weather was like during the life of that tree. Trees grow quickly in warm, moist climates, creating wide tree rings. Subsequently, trees grow slower and the rings are closer together during drier, more stressful periods.

Accurate weather records have been kept since the late 1800s. Scientists compare local tree rings to known weather data and then infer what the past climate was like from the rings of much older trees. Core samples can be taken from living trees without harming them.       

To understand past climates on a global scale, climatologists study ice cores drilled from glaciers. Atmospheric particles and gases that were trapped in the fallen snow accumulate over time and leave a record of ancient climatic conditions – frozen time capsules. These ice cores are then correlated with other samples taken from around the world.

Sedimentary rocks form in a similar manner, providing information about climates throughout geologic time. Satellites record changes in the atmosphere, oceans and land masses. All of this data informs scientists’ understanding of how changes on our planet affect climates over time. Computer generated climate models are then used to predict climate changes based on this information.   

The USDA Hardiness Zone Map is the standard that gardeners use to determine which plants are suitable for growing in their area. The USDA revised its hardiness zones in 2012. The higher the number, the warmer your average low temperature each winter. We saw our zone in Leavenworth rise from 5b to 6a, an increase of 5 degrees. As gardeners, we must adapt to a changing climate and adjust our gardening practices accordingly.

Rachel and Ivan Minnis are avid gardeners. They live in Leavenworth. For more information, visit The Minnis Rose Garden on Facebook. Contact them at rnlyes@hotmail.com