If the weather forecast for the rest of the month is accurate, we'll receive less than one inch of precipitation this December when the month ends on Sunday. Since we live in a Mediterranean climate in the northern hemisphere, we expect December to be one of our rainy months (and in the 16+ years we've lived in Auburn, we've averaged nearly 7 inches of rain in December). This average, however, masks the variability in our December precipitation - in 2011, we measured just 0.10 inches; in 2005, we had 13.48 inches. During our recently concluded (?) 500-year drought (2012-2015), we received between 0.50 inches (2013) and 11.62 inches (2014). Extremes, it seems, might be our new "normal" weather.
As a rancher who relies on the grass that Mother Nature provides, this variability presents challenges for grazing our annual grasslands. For a variety of reasons, we don't (can't!) irrigate these grasslands - the grass we harvest with our sheep from November through April needs rain to grow. December and January, with their short days and (relatively) cold temperatures, are our dormant months in terms of grass growth. Even so, the rains that fall in December and January are critical for the soil moisture that will support the forage we need (and expect) when our ewes enter late gestation and begin to deliver their lambs in late February.
December is also a critical month for building the Sierra snowpack that will fill the High Sierra reservoirs that store and supply our irrigation water during the summer months (we need irrigation for the green grass our sheep need in the summer). While these reservoirs are far above their seasonal averages (thanks to last year's record setting precipitation), there is very little snow in our high country. Usually, rain in the Sierra foothills becomes snow in the high mountains - no rain means no snow, either.
I'm not a climate scientist by any stretch of the imagination - but I have paid close attention to the weather for more than half of my 50 years in this region. While variability has always been a feature of our foothill climate, the extremes (of dry and wet) seem much more pronounced to me. The climate also seems warmer, in general - snow days were not uncommon when I was a school kid in Tuolumne County; my parents have not had much snow at the home I grew up in during the last 10-15 years. The climate, it seems to me, is changing.
All of this brings me to my point, I suppose. Politicians can debate about whether our climate is changing (and, more importantly, about whether human activity is responsible for this change). Overwhelming scientific evidence suggests that the climate is changing and that humans have contributed to this change in significant ways. These debates don't help me address the realities of grazing sheep on annual rangeland in the Sierra foothills. The challenge for me, on a daily and yearly basis, is to adapt to these changes. The challenge for me is to increase the flexibility of our sheep enterprise. The challenge for me, ultimately, is to adapt to this new normal - to this new variability.
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