We’ve all heard about the disappearing polar ice caps, rising sea levels, and emerging crazy weather patterns around us. But discovering these environmental changes didn’t happen overnight – lots of careful research goes into the field of climate science, and there’s more work being done every day to explore details about phenomena triggered by global warming. July has been particularly abuzz with articles in this field; below, I’ve summarized a few of the papers and news items from the summer.
Disclaimer: I am not a climate change expert. There are several other recently published articles in the field; the ones I included are those that I found easy to understand from an outside perspective.
“Climate change and wind intensification in coastal upwelling ecosystems”
In 1990, a man named Andrew Bakun predicted that global warming would cause an increase in something called upwelling winds. This is a phenomenon in which winds drive cooler and more nutrient-dense water up toward the ocean surface, replacing the warmer water already there. Many smaller studies have previously been done to investigate the validity of the prediction; in this article, the authors did a meta-analysis on 22 studies to determine how upwelling wind patterns have changed. They concluded that upwelling winds have indeed intensified in the summers over the past 60 years, and they have intensified near the poles year-round. So what does this mean? In the short term, it could actually be a positive thing: more nutrients being brought up means increased plankton, which means more fish – therefore, better both for natural oceanic ecosystems as well as for human fishing purposes. There’s a catch, though: This benefit will likely be short-lived. If upwelling wind strengths continue to increase, ocean surfaces could become too acidic or oxygen-deprived, crashing the food chain. Plankton and other small organisms could be also pushed off the continental shelf altogether, which would be bad news for fish, fishermen, and sushi fans.
“Climate change selects for heterozygosity in a declining fur seal population”
Save the Antarctic fur seals!
It can be hard for scientists to pinpoint how different species are being affected by climate change, because it requires detailed data following a specific population. Fortunately, the authors of this paper have over three decades of data from a specific population of Antarctic fur seals. Unfortunately, it looks like the seal numbers have been declining, likely due to a decline in krill, the seals’ food of choice, as krill don’t fare as well in changing sea temperatures. This decline in krill in turn led to a 24% decrease in breeding females, and an increase in first age of reproduction, both leading to less breeding overall. Additionally, the average birth weight of female pups is 7.8% lower since 1987. The authors hope, however, that the more evolutionarily fit seals will be able to sustain the population long enough to adapt to changing conditions, rather than face extinction.
“Nonlinear permanent migration response to climatic variations but minimal response to disasters”
So how does global warming immediately affect people? This study examined a human response to climate change: migration. Studying populations in Indonesia, the authors found that increased temperature alone leads to a non-linear increase in migration – meaning that a one-degree difference in temperature from 26° C to 27° C led to a 0.8% increase in migration, but a one-degree difference from 27° C to 28° C increased the rate of migration by almost double that amount. Why does temperature play a role in people’s migratory habits? Other studies have shown that increased temperatures lead to decreased agricultural productivity, probably causing people to move for economic reasons. Furthermore, warming temperatures are accompanied by heightened rainfall and resulting landslides, making safety a motivator for migration (interestingly, other natural disasters did not seem to correlate with migration). While this may affect coastal and farming regions the most at the moment, climate-forced migration could impact everyone’s livelihoods someday.
A recent New York Times article discusses how increased carbon emissions are causing the death of billions of oysters in the Pacific Ocean. I actually found this news to be the most eerie – it almost sounds like the start of a sci-fi thriller, with species mysteriously starting to disappear. Unfortunately, it’s not fiction, and we need to make some changes.
The bad news: new estimates say that for every decade we postpone any measures to curb global warming, the costs for reducing its effects goes up by 40%. Read the White House report here: http://www.whitehouse.gov/sites/default/files/docs/the_cost_of_delaying_action_to_stem_climate_change.pdf
The very good news: Not everyone is procrastinating! USAID and the Rockefeller Foundation are partnering up to try to protect low-income families from the negative effects of climate change (perhaps such as the migration problems discussed above). This $100 million project will also aim to improve natural disaster predictions.
The future news: Two letters in PNAS this summer discussed how to control carbon emissions. The first article suggested a control-based approach: for example, the US would be responsible for all the emissions produced in China by US multinationals, not just the emissions produced on US soil. The authors estimate that this means that the US produces “65% more CO2, 68% more nitrogen oxides (NOx), and 66% more sulfur oxides (SOx) emissions” than currently assigned. A response to this letter says that this method might not actually lower total emissions, and that the US would still benefit from cleaner air while China would have to suffer pollution. They suggest instead that the final consumer of a product would have to be taken into account to determine who is responsible for the emissions.
From this research, it seems to me there are at least two things going on with global warming: first, changes to ecosystems that will catch up with us faster than we realize, and second, direct, weather-related impacts on human life. But, there are many more facets of the climate change discussion – stay tuned to the blog for more coverage