I believe the most common cause of dessert on earth is humans. The process is actually called desertification. It usually involved deforestation, poor farming practices, poisoning the ground, and a natural tendancy to low precipitation.

However you state that this is a land that is "one" with nature.

#Option #1. Past Perhaps the people are one with nature because of what they did to this island.

#Option #2 Cataclysmic force. An earthquake, meteor, tsunami, volcanic eruption, or magical beast could have caused this.

#Option #3 End of the world. I think the sun is actually supposed to get colder as it gets older but a decaying orbit might draw the planet closer to the sun. This would result in storms, heat waves, unpredictable weather and general chaos. Wouldn't likely spare the other islands though.

I believe the most common cause of dessert on earth is humans. The process is actually called desertification. It usually involved deforestation, poor farming practices, poisoning the ground, and a natural tendancy to low precipitation.

However you state that this is a land that is "one" with nature.

Option #1. Past

Perhaps the people are one with nature because of what they did to this island.

Option #2 Cataclysmic force.

An earthquake, meteor, tsunami, volcanic eruption, or magical beast could have caused this.

Option #3 End of the world.

I think the sun is actually supposed to get colder as it gets older but a decaying orbit might draw the planet closer to the sun. This would result in storms, heat waves, unpredictable weather and general chaos. Wouldn't likely spare the other islands though.