What Triggered the Two-Million-Year Rain That Made Dinosaurs Possible?

And what lessons can we learn from that event?

Have you had these situations where something seemingly bad happened, but its consequences changed your life for the better? Two years ago, I was actively interviewing for faculty positions in some of the most prestigious universities in the country.

One of these interviewing processes seemed to be going amazingly well. I clicked with all the other professors in the department almost immediately. I liked the campus; everyone seemed excited about the units I would teach and the graduate students I would advise.

I was 37 weeks pregnant on the two days of the fully remote campus interview. They were interviewing other candidates in the following weeks, so I knew I would hear from them after I had my baby.

The baby came, the postpartum recovery went, and I still hadn’t heard from them. At this point it was obvious: I didn’t get the job. However, my new life as a parent of two made me make an important decision. I was going to quit academia and move back to DC to be closer to my husband’s family. This was probably the hardest decision of my life.

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For a few months, though, I felt some resentment. I felt I was the perfect fit for the job; why didn’t I get it? Then hurricane season came and hit the city where this university was very hard. When I checked the maps of the most affected areas, I froze. They included the area where we would have bought a house. Had I gotten the job, we would have lost everything while caring for a toddler and a newborn baby.

I felt terrible for all the faculty at that university, but in a way, I found closure. That rejection saved us.

Indeed, it often happens that seemingly bad things are the best that could have happened to us. For example, I previously talked about the 2 million years of rain that transformed Earth and set the stage for the dinosaurs (yes, it’s about rain today). Such an event sounds terrible on paper, but it actually helped a whole group of animals thrive.

In that article, I asked if you’d be interested in learning why this ultimately caused this prolonged downpour and what it can teach us about our current climate situation. I received many requests to cover it, so let’s explore the mystery behind this ancient weather phenomenon.

This period of intense rainfall, known as the Carnian Pluvial Episode (CPE), happened around 230 million years ago. Scientists believe it was triggered by a series of volcanic eruptions in what is now western North America, specifically the Wrangellia Large Igneous Province.

However, these eruptions were not your average volcanoes; they were massive and spewed enormous amounts of carbon dioxide (CO2) and other greenhouse gases into the atmosphere.

And, you know the story from here: this sudden influx of CO2 caused significant warming on the planet.

Think of it as a prehistoric greenhouse effect on a massive scale. The warming led to increased evaporation of water from the oceans, which in turn resulted in more clouds and, eventually, more rain. The intense volcanic activity also released other gases like sulfur dioxide, which can form aerosols in the atmosphere.

These aerosols might have initially caused some cooling by reflecting sunlight, but as they settled out of the atmosphere, the long-term warming effect of CO2 took over.

As the rain persisted, it caused widespread changes in Earth’s ecosystems. On the other hand, the constant downpour led to erosion and flooding, transforming arid landscapes into lush, green environments.

This sudden shift in climate created new habitats and resources, allowing early dinosaurs and other life forms to adapt and thrive. But it wasn’t just the dinosaurs that benefited; plants, particularly ferns and other moisture-loving species, took advantage of the wet conditions to spread and diversify. Ultimately, ecosystems are always built form the ground up, starting with the primary producers (aka. plants).

However, the CPE wasn’t just about rain. As it turns out, the changes in the carbon cycle and the prolonged wet conditions also led to fluctuations in sea levels and ocean chemistry. Research indicates a significant global sea-level fall during this time.

This would have exposed more land, creating new environments for life. But things didn’t stop there. Simultaneously, ocean acidification caused by the volcanic CO2 influx led to a crisis in carbonate production, affecting marine ecosystems. This period saw many biogeochemical processes followed by a recovery that marked the beginning of new marine life.

So, you know I was going there: what does this ancient event tell us about our current climate crisis? The CPE serves as a reminder of how interconnected Earth’s systems are. A sudden change in one part of the system, like volcanic eruptions increasing atmospheric CO2, can set off a chain reaction affecting climate, ecosystems, and even the structure of the oceans.

Today, we’re witnessing a similar situation, but this time it’s driven by human activities, primarily the burning of fossil fuels.

The parallels are hard to ignore, though. Just as the volcanic eruptions of the CPE led to a rapid increase in greenhouse gases and global temperatures, our current emissions are causing a comparable rise in CO2 levels.

The difference is that while the CPE’s greenhouse gas emissions were a natural event, ours are largely preventable. Or it could have been. We’re creating our own version of the CPE, with potentially dramatic consequences for the planet.

One key takeaway from the CPE is the planet’s capacity for change and adaptation, the limits to how much change ecosystems can handle, and the long periods it takes for change to occur. Do you have a couple million years to spare?

The CPE caused a massive reshuffling of life on Earth, with many species going extinct while others took advantage of new opportunities. In today’s world, we’re seeing similar shifts, with many species struggling to survive in the face of rapid climate change, habitat loss, and ocean acidification.

On the other hand, the CPE also highlights the importance of understanding feedback mechanisms in Earth’s climate system. During the CPE, the initial volcanic activity set off a series of feedbacks, such as increased rainfall and changes in ocean chemistry, which amplified the effects of the initial event.

In our current climate crisis, feedbacks like the melting of polar ice, which reduces the planet’s albedo (the fraction of light that a surface reflects), and the release of methane from thawing permafrost, are accelerating climate change.

The 2 million years of rain during the Carnian Pluvial Episode were a natural experiment in rapid climate change. They show how a sudden increase in greenhouse gases can lead to environmental shifts and serve as a cautionary tale for our own time.

While the CPE paved the way for the dinosaurs, our current path may not be as forgiving if we don’t take steps to mitigate our impact on the planet. Understanding these past events can help us make better decisions for the future, ensuring that our story doesn’t end the way it began — with too much rain and too little foresight.

We were lucky that something good emerged from a negative event in the past. Will we be this lucky twice?