Tag Archives: climate change

Yes, sea level rise really is accelerating

Enlarge / A family of sea-level-measuring satellites. (credit: NASA)

Some people have eyeballed satellite measurements of sea level rise and claimed that there is no sign of acceleration—just a linear increase. Then, ignoring the physics of melting glacial ice and the expansion of warming water, they declare that future sea level rise won’t be a big deal. Many studies have demonstrated accelerating rates of sea level rise over the past millennia, as well as the tide gauge record spanning the 20th century. But the short satellite record—which only started in 1993—is a slightly different question.

While the global satellite record is in many ways cleaner than coastal measurements that can be affected by processes that raise or lower the ground that the tide gauge sits

Read the rest

Can we zero-in on Earth’s sensitivity to CO₂?

Enlarge (credit: Kristin Andrus)

If it were easy to pin down the exact value for our planet’s sensitivity to greenhouse gas emission, it would have been done a long time ago—and you wouldn’t be reading yet another news story about it. It’s not like we have no idea how sensitive the climate is. The range of possible values that scientists have been able to narrow it down to only spans from “climate change is very bad news” to “climate change is extremely bad news.”

But the difference between “very bad” and “extremely bad” is pretty important, so climate scientists aren’t throwing up their hands any time soon—as two new studies published this week show.

There are several basic strategies available for calculating the climate’s sensitivity.

Read the rest

As climates cool, adaptation heats up

Enlarge (credit: Getty Images / DEA Picture Library)

While natural selection is a big part of evolution, the theory now embraces much more than that. One of the big concepts that explains a lot of the pattern of evolution throughout history is called “adaptive radiation.” Adaptive radiation is a process in which environmental changes create new resources, challenges, and environmental niches, enabling rapid diversification of organisms from a single ancestral species.

Adaptive radiation provides a sound explanation that captures the effects of the interactions among organisms on species diversification. However, non-biological effects—the details of how environmental changes interact with species—are not easy to incorporate into this model and have not been extensively explored.

In a recent investigation published in PNAS, a team of scientists

Read the rest

How globalised agriculture is ruining lives in South America

Not much remains of Guayaqui Cuá in southeastern Paraguay. As fires continue to smoulder, wisps of smoke float over the charred slats of a wooden bed, burnt personal possessions and a few sombre peasants living under makeshift plastic tents, which are all that’s left of this small rural community.

Two days ago, security men from the nearby cattle ranch and local police officers, under orders of a large estate owner, moved in without notice to evict the community and raze their properties to the ground, explains a tearful María Lina Estorales. Sitting despondently on the dirt floor and wiping rivers of tears from her face, she’s trying to work out what to do next – surrounded by members of the other 21 families who lost their … Read the rest

If you live inland, don’t think sea level rise won’t affect you

Enlarge (credit: flickr user: Richard)

There has been a lot of talk about the millions of people worldwide whose homes will be at the mercy of rising sea levels. Within the US, a 1.8-meter rise in the oceans by 2100 could displace as many as 13.1 million people. Worldwide, up to 180 million people could be at risk.

There has been less talk about where exactly those people will go when they leave their homes. Research on climate migration has painted sea level rise as “primarily a coastal issue,” writes Mathew E. Hauer in Nature Climate Change this week. But the inland regions that absorb climate change migrants will need to have sufficient transport, housing, and infrastructure to absorb the migrants.

To get a picture

Read the rest

Once more with feeling: Climate models don’t exaggerate warming

Enlarge (credit: NASA’s Scientific Visualization Studio and NASA Center for Climate Simulation)

If you follow climate science news, you know that one of the hotter topics is “climate sensitivity”—the precise amount of warming you get for a given increase of greenhouse gases. A few years ago, a couple papers caused a stir by trying to estimate this sensitivity based on simple equations for the recent past, coming up with a lower warming sensitivity than numerous other studies based on climate models or paleoclimate records. The last IPCC report even widened its estimated range slightly to encompass these studies, which proved controversial.

Researchers have already found reasons to think those low sensitivity estimates were problematic, including the fact that the simplistic, global representations of warming and

Read the rest