Though the waters are risin’ still no surprisin’ you

That’s how the lyrics of a song I often listen to allude to the fact that despite the real possibility of impending undesirable changes, some remain unconcerned. When it comes to climate change and sea level rise, some not only remain unconcerned, but actively engage in rolling back climate change mitigation efforts. Despite the fact that a vast majority of U.S. citizens think that global warming is happening, and support the regulation of carbon dioxide, the new leadership’s decision not to focus on critical issues like climate change represents a potential halt to any action that intends to protect the environment. The budget proposal for 2018 calls for a 31% budget cut to the Environmental Protection Agency (EPA) – to the lowest levels that the EPA’s budget has been in four decades. In the spirit of austerity, Budget Director Mick Mulvaney defended the proposal and stated that the White House considers any program related to climate change “a waste of…money.” Additionally, it is concerning that climate change denial has supporters in Capitol Hill that believe the planet is not warming or that  human activity is not a main contributor to anthropogenic climate change. In the current political context, where climate change denial is a new ‘alternative [environmental] fact,’ the facts of science become an important tenet of an agenda to protect the environment and follow a sustainable way of living.

 

Installation in Berlin 2011 by Isaac Cordal – “Politicians Discussing Global Warming”

 

The first science-based fact I would like to talk about is sea level rise, a specific and highly visible impact from climate change. Though polar ice sheets melting is an important factor, the largest source of sea level rise comes from the warming of the ocean – also known as the thermal heat expansion. In other words, as the ocean gets warmer, the seawater density decreases, thus increasing its volume. There are two additional factors that contribute to sea level rise. A previously underestimated factor that has been recently getting more attention among scientists is the impacts on sea level from taking water out of the ground for industrial and residential consumption or agricultural uses. Second, the excessive extraction of resources, like mineral resources, below ground (a human activity) can lead to changes in the relative level of the sea. Scientists know sea levels have been rising from observing over 100 years of data from tide stations. These stations collected data from tide gauges, and, in recent years, from microwave sensors and GPS. In the last twenty years or so, scientists have gotten sophisticated tools to measure the surface of the ocean with satellite radar altimeters. These satellites are high precision tools that “emit a radar wave and analy[ze] the return signal that bounces off the surface.” Data from altimetry satellites suggest that the sea level has been rising 3.4 mm per year.

 

 

There is evidence that Greenland, Antarctica, and the tropical ice sheets are melting. Scientists are using the GRACE (Gravity Recovery and Climate Experiment) program to detect gravitational changes in ice sheets. GRACE consists of a pair of satellites that follow one another around the Earth detecting changes in gravitational fields. As ice sheets melt, the density fluctuations affect the gravity in a given area. GRACE has an “extremely precise microwave ranging system that detects…miniscule changes” in gravity and a GPS that determines “the exact position of the satellite over the Earth.” Similarly, CryoSat, a satellite that measures the thickness of the ice in Antarctica and Greenland, provides valuable information on how the volume of ice is changing in these locations. By combining the power of these two highly precise tools, scientists estimate the changes in the mass of the ice sheets in both Greenland and Antarctica. Greenland has been losing approximately 281 gigatonnes of ice per year since 2002, and Antarctica has been losing about 118 gigatonnes per year (24 cubic miles of ice per year). Lonnie Thompson’s work over several decades has also demonstrated that the tropical ice sheets have been retreating. He and his team have been collecting observations on the ice sheets in different places in Africa, Asia, and South America. There is evidence of the declining mass of ice sheets in places like Mt. Kilimanjaro, The Himalayas, and the Qori Kalis glacier. The graphs below [reproduced from NASA] illustrate the declining mass of Antarctic and Greenland ice over time, and the pictures below display the loss of ice in the Qori Kallis glacier in the Andean Mountains of Peru.

 

 

 

When one thinks about the fact that seawater is expanding and ice sheets are melting, and connecting them to the sea level rise, images of flooded coastal cities may come to mind. Two examples of cities tackling the rising waters in the US are Atlantic City and Miami Beach. Atlantic City, with a population of 40,000, with more than 70 percent of its population living below the poverty line, will have a sea level rise of 1.5 feet in the coming decade. Considering the additional challenges that communities and individuals with fewer resources face, the socio-economic characteristics of this population present additional, and dire, challenges when faced with sea level rise. If we travel south, the City of Miami Beach is also fighting the projected oncoming sea level rise. Estimates suggest that Miami Beach will experience sea level rise of 2.39 mm per year, which is equivalent to 0.78 feet in 100 years. The city is investing $100 million to install pumps, raise roads, avoid the intrusion of saltwater into freshwater supplies, and take measures to prevent seawater rise from causing damage to the city. One might think that the easiest thing to do is to sell your house, get your things, and move further inland, but a couple of facts should be taken into consideration. The numbers of people living in coastal cities are increasing. The estimate is that 47 percent of the US population will be living in coastal areas in 2020, a raise from 39 percent in 2010. Furthermore, moving might not be feasible for economically challenged populations. This all begs the question of what action lawmakers should take in response to continuing climate change, rising sea levels, and rising coastal populations.

 

Image courtesy of Flickr. Originally published by S&S on April 26, 2017.

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