Longer, hotter heatwaves. Larger and more frequent wildfires. Less snowpack and water reservoirs that remain stubbornly low.

We're already seeing the results of a warming planet. But it could get a whole lot worse, scientists continue to warn.

A new study found that we might be heading toward a "hothouse Earth" scenario in which natural feedback loops -- such as massive methane release from melting permafrost -- would crank up the warming of the planet to disastrous levels. If this happens, even the ending of fossil-fuel emissions wouldn't arrest it.

"If the threshold is crossed, the resulting trajectory would likely cause serious disruptions to ecosystems, society and economies," states the study, titled "Trajectories of the Earth System in the Anthropocene."

The paper is published in PNAS (Proceedings of the National Academy of Sciences of the United States of America).

"These tipping elements can potentially act like a row of dominoes," Stockholm Resilience Center executive director and study co-author Johan Rockstrom said this week. "Once one is pushed over, it pushes Earth towards another. It may be very difficult or impossible to stop the whole row of dominoes from tumbling over."

The conventional wisdom in the scientific community is that global warming of about 2 degrees Celsius above pre-industrial levels could be the tipping point for the climate, causing unstoppable warming up to 5C -- "a much higher global average temperature," the study notes, "than any interglacial in the past 1.2 million years." Right now, the Earth is a little over 1C above the pre-industrial period.

The study is not all doom and gloom. Possible solutions, it states, include "decarbonization of the global economy, enhancement of biosphere carbon sinks, behavioral changes, technological innovations, new governance arrangements and transformed social values."

-- Douglas Perry