If you live in the United States, you probably associate the Sierra Nevada mountains with California. But if you live in Europe, you probably think of the Sierra Nevada mountains located in Granada, Spain. Yes, if you weren’t already aware –– there are two huge mountain ranges, on two different continents, both of the same name.

The similarities don’t end there either. Both are being increasingly affected by climate change.

Up in Flames

In California, wildfires are one of the biggest problems plaguing Sierra Nevada. Heat and dryness resulting from drought and increased temperatures have caused wildfires to increase in intensity, quantity and frequency. According to California’s Department of Forestry and Fire Protection (CAL FIRE), nine out of ten of the state’s largest wildfires have occurred in the last decade. The trend is likely to continue, as one study suggests the number of fires could increase by about 20 percent or more by 2040.

Jessica Morse, Deputy Secretary for Forest and Wildland Resilience within California’s Natural Resource Agency and board member of Sierra Nevada Conservancy, put it simply.

 “You’re seeing drought plus heat precipitate catastrophic fire,” she said. “You have like 200 days without rain and in some of these areas you’re getting no moisture and it’s causing the fire season to get longer and longer and longer to the point that now it’s basically become year round.”

Wildfires actually play a crucial role in Sierra Nevada’s ecosystem and have done so naturally for centuries. Fires can clear out dead organic material. allowing nutrients to return to the soil and new plants to grow. Yet, more recent fires have gotten out of hand –– in large part due to human interference. 

There are a number of factors here, from the forced removal of Indigenous people who practiced vital cultural burnings, to the clear-cutting during the gold-rush era that wiped out many fire-resilient trees. This was further compounded by a policy of fire suppression by the forest service for most of the 20th century. Now, a strand of overly dense and weak trees that burn easily and fast is all that remains.

Spain’s Sierra Nevada has a similar history of human interference, with mass deforestation resulting from factors such as mining activities and privatization of forest land, which was then converted to pastures or arable land once sold.

In the late 1930’s, a major reforestation plan was formulated during the final years of the Spanish Civil War. While it was recognized that forest regeneration was urgently needed, the plan also provided much needed jobs in a time where hunger and unemployment were rampant in the face of the dictatorial regime that emerged in the post-war era.

The program proved successful on a number of levels –– nearly 275,000 hectares were planted in the first decade of the program and in total 2.9 million hectares of trees were planted between 1940-1983. Rainfall was higher than average during this time and the wide scale planting helped deal with ongoing issues of soil erosion. As intended, many jobs were created in the process, as the work did not require much specialization.

Yet, there was a problem; nearly 85% of the trees planted were pine species. Though not known at the time, the lack of diversity in plant life and thick density of the forests would make for increased risk of fire as the years progressed.  

As Blanca Ramos, member of Sierra Nevada’s Global Change Observatory put it, “It is a totally homogenous territory with no diversity in terms of age or structure or species. These systems are extremely vulnerable, for instance to fire.”

This has proved overwhelmingly true. From 1961 to 2005, almost 2.75 million hectares were burned, which represents 93% of the area reforested between 1940 and 1983, meaning a majority of the work has been undone. 

It might seem obvious in hindsight that a lack of biodiversity could lead to issues down the road. Yet, as Jorge Castro, a professor of Ecology at the University of Granada pointed out, these trees were planted far before science or forest studies found the flaws in planting a monoculture.

“These pines were selected according to the dramatic conditions that were prevalent 60 or 70 years ago and, at that moment nobody talked about climate change,” Castro said. “These trees are adults now and they are very dense, so there are not enough resources for them. These plantations are debilitated; it is not a very healthy situation.  

Spain’s wildfires occur on a much smaller scale than in the United States. For instance, Spain’s biggest wildfire in 2021 scorched around 10,000 hectares of land while California’s 2021 Dixie fire burned through over 350,000 hectares. 

As Castro explained, the forests in Spain are much smaller so there is less to burn –– but, on a relative scale, wildfires are still ravaging ecosystems.

“If you have 1 million kilometers of forest and half is burnt, you still lose half of the forest, so it’s a big issue.” he said.

In the face of increasing wildfires, both California and Spain are now trying to reverse these effects. 

Fighting Fire with Fire

In September 2021, California’s Governor Gavin Newsom signed a $15 billion package to tackle the climate crisis, $1.5 billion dollars of which will go toward wildlife and forest resilience efforts. The effort marks the largest investment in the climate crisis in the state’s history. 

According to Morse, the $1.5 billion investment package will largely be distributed to the California Natural Resources Agency and will be spread across 21 different departments, including the California Department of Forestry and Fire Protection and the Sierra Nevada Conservancy.

Morse said the CNRA plans to implement the funds on three fronts: putting in defensible space and home hardening so communities and their homes can potentially withstand fires; strategic fuel break around these communities so firefighters have a place to steer the fires away from homes; and finally working to return fire to it’s natural ecological role through forest restoration.

The last part is crucial and will be done through a process known as prescribed, or controlled, burning in which parts of a forest are intentionally burned in order to maintain forest health and protect against more extreme fires. 

As Morse explained, controlled burning helps safely reduce excessive amounts of brush and trees, ensuring future fires will not spread as far out of control. She added these fires are planned well in advance and at times when weather conditions are such that the fire will not spread out of control. 

”When a fire does strike, it burns at a low intensity level and plays an ecological role germinating seeds, improving diversity,  and improving the watershed as opposed to the catastrophic role of wiping everything out,” Morse said.

Prescribed burning is becoming an increasingly popular solution around the country as a way to mitigate fires and it has proven effective in a number of wildfires. As one example, when the 2021 Caldor Fire ravaged parts of California, South Lake Tahoe managed to avoid much of the damage in part due to prior prescribed burning.

While more people are coming around to the idea, there is often pushback against the idea of controlled burns, especially among people who are new to the concept. As Jamie Ervin, a fire restoration advocate and former member of Sierra Forest Legacy, a non-profit dedicated to the protection, restoration and management of Sierra Nevada, explained, it can be difficult for people to fathom how starting more fires could actually help prevent fires in the future.

“I think people get it to a large part, but, when it actually comes to lighting something near where people are, that can be challenging. You could run into a lot of resistance from folks, especially if it’s a private landowner doing burning instead of a federal agency or something like that,” he said.

Cut for Time

In Spain, prescribed burning is barely considered an option due to negative public sentiment, according to Castro.

“Not in Sierra Nevada, not in Spain, I will say not in the Mediterranean basin … this is taboo,” he said. “It could be a good option to manage the environment but, there is such a concept of fires being something really bad, that society cannot accept that you burn the forest to control the future fires.

It’s not necessarily ignorance or a lack of education driving this sentiment. As Castro explained, many people have spent all their lives hearing about or working firsthand on reforestation efforts. Proposing to burn the very pine trees that were the long-time focus of the reforestation efforts can seem completely backwards.

“For decades people, the forest service, and the citizens, and the villages have been putting in huge effort to cultivate these trees to have a non-natural forest but a forest nonetheless,” he said. “Imagine you’ve spent your life like that and your son has spent his life like that and now you go and say, ‘Don’t worry guys, we are going to solve all the problems here. We are going to burn the forest.’ They cannot understand that.”

Castro said instead much focus is put into thinning the forest by cutting the lower branches of the pine trees and removing shrubs and brush along the sides of busy roads. This helps prevent fires from starting on the ground and can ease the spread of fires if they do occur.

Planting native and diverse plants alongside the pines to naturalize the existing pine forests is another solution. Ramos said this a primary focus of the Sierra Nevada Global Change Observatory (OBSNEV), an organization that studies the long term effects of climate change in the mountains. Still, Ramos said even though scientists and workers at the observatory know how to implement this plan, the process is time-consuming and expensive and could take decades to reach fruition.

“It is very expensive to transform an artificial forest covered by pines into an area with brush, meadows and rivers,” she said. “You have to introduce diversity and you cannot do it in one single project. You have to do it in different phases and it takes a lot of money.”

Climate Change Versus Global Change

Unlike the California Natural Resources Agency, the Sierra Nevada Global Change Observatory doesn’t have a $1.5 billion investment package on their hands. Still, OBSNEV is a unique organization in and of itself and proof that the Spanish government is aware and dedicated to solving this issue.

As part of a larger network of global observatories formed under UNESCO, OBSNEV emphasizes global change rather than climate change. Ramos said at times it is difficult to separate issues of climate change from human involvement in the change of landscapes over time.

“We speak about global change, not only climate change, because we found out that one of the most important drivers of change in Sierra Nevada has been the use of the land,” she said.  “Of course climate change is also very important, but we’d prefer to refer to the changes that occur as a more global group of factors that also includes invasive species and contamination and other global phenomena.”

This proves true in Spain, California and elsewhere. As Erwin described California’s wildfire problem, “The biggest threat to the forest in Sierra Nevada, other than climate change, is fire exclusion. And the fact that we’ve excluded fire from these forests that would have burned every five to twenty years prior to European settlement and removal of Indigenous Californians. There’s also been so much development over the last 50 years of people putting houses in fire prone areas, so there’s way more buildings and human infrastructure for fires to burn up.”

So yes, climate change is a huge driver of wildfires but it’s easy to forget that behind this big idea of global warming are humans who for centuries have drastically modified landscapes. We can successfully combat wildfires with reforestation techniques, but at the same time we should also be aware of other ways in which we shape our surroundings, such as how we manage our forests and where and how we build homes in these fire-prone regions.

If the two Sierra Nevadas teach us anything, climate change is a global issue that everyone plays a part in.