A must-read: Sea-level rise and climate change, explained

IF YOU WANT TO cut through all the noise and confusion about climate change, read this. This is important. Feel free to share. The more we know, the better able we'll be to respond to the challenge.

Ben Horton is in the Department of Marine and Coastal Science at Rutgers University, and spoke at the Delaware Estuary Science and Environmental Summit on Jan. 22, 2017.

The facts of sea-level rise, global warning and climate change were pretty well understood by this audience — but the room was spellbound as Horton took us on a journey from the past to the future and what that future might look like.

So I asked him to respond to five questions and he kindly agreed.

1. First (and I just keep coming back to this one, unfortunately): How bad is it? How soon will the effects take hold? Will it be within my lifetime? Is there even any point to trying, or is it a lost cause? Before even getting to "it," perhaps a better definition of "climate change" is needed. I tend to think of it as two things: changing weather patterns and sea level rise. The secondary effects, then, are things like population destabilization, food scarcities, "natural disaster", and general social and political chaos. Are there others that I'm missing?

Our Earth is warming. Earth's average temperature has risen by 1.5°F over the past century, and is projected to rise another 0.5 to 8.6°F over the next hundred years. Small changes in the average temperature of the planet can translate to large and potentially dangerous shifts in climate and weather.

The evidence is clear. Rising global temperatures have been accompanied by changes in weather and climate. Many places have seen changes in rainfall, resulting in more floods, droughts, or intense rain, as well as more frequent and severe heat waves.

The planet's oceans and glaciers have also experienced some big changes — oceans are warming and becoming more acidic, ice caps are melting, and sea levels are rising. As these and other changes become more pronounced in the coming decades, they will likely present challenges to our society and our environment.

The difference between weather and climate is a measure of time. Weather is what conditions of the atmosphere are over a short period of time, and climate is how the atmosphere "behaves" over relatively long periods of time.

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    A distinguished career

    Dr. Benjamin Horton is a Professor at the Department of Marine and Coastal Science of Rutgers University. His research concerns sea-level change. He aims to understand and integrate the external and internal mechanisms that have determined sea-level changes in the past, and which will shape such changes in the future.Ben Horton has published over 180 articles in peer-reviewed journals, including Science, Nature, Proceedings of the National Academy of Sciences, and Geology.Dr Horton is supervising or has supervised 21 students to the degree of PhD and 11 postdoctoral scientists, of which 12 now occupy academic positions (9 as Assistant Professors or comparable positions).Dr. Horton has received awards from European Geosciences Union (Plinius Medal 2016), American Geophysical Union (Voyager Award 2014) and the Geological Society of America (W. Storrs Cole Award 2007). He was made a Fellow of the Geological Society of America in 2013. He is an author of the Intergovernmental Panel on Climate Change (IPCC) 5th Assessment Report (5AR), a committee member of PALSEA (PALeo-constraints on SEA-level rise), and was a project leader of International Geoscience Programme (IGCP) 588.

When scientists talk about climate, they're looking at averages of precipitation, temperature, humidity, sunshine, wind velocity, phenomena such as fog, frost, and hail storms, and other measures of the weather that occur over a long period in a particular place.

The reason studying climate and a changing climate is important. Climate change affects people and nature in countless ways, and it often increases existing threats that have already put pressure on the environment. Human migrations because the impacts of climate change on water and food is a huge concern. We only have to look at the news in the last several months to be aware of the problems and challenges that mass migration poses. Climate change will have major and unpredictable effects on the world's water systems, including an increase in floods and droughts, causing displacement and conflict. Less fresh water means less agriculture, food and income. Climate change will have a significant impact on food availability, food accessibility, food utilization and food systems stability in many parts of the world. Climate change poses a significant risk of increased crop failure, loss of livestock and will impact on local food security.

Scientists have hope for the climate. In 2015 the world finally came together in Paris where a landmark climate pact was agreed to try to put a cap on greenhouse gas emissions. Then we had the papal encyclical, which called for an ethical and economic revolution to prevent catastrophic climate change and was sent to the world’s 5,000 Catholic bishops and published in five languages. As such every Catholic parish, school and university will teach to it.

I hope the nation will become fully aware of the urgent nature of action on climate change. The impacts from climate change are expected to intensify in the coming decades. If we don't act now, climate change will rapidly alter the lands and waters we all depend upon for survival, leaving our future generations with a very different world.

2. Speaking of sea level rise — and I should know this, but, sadly, have never really understood it — when they talk of "feet," what does that mean, exactly? Is that vertical feet (depth) or amount that the shoreline is shifting? How much of this is now a given?

Sea-level rise is the vertical increase height of ocean surface relative to a fixed point on land. One of the principal impacts of sea-level rise will be the loss of land in coastal areas through erosion and submergence of the coastal landscape.  Erosion caused by higher sea level results from subjecting previously out-of-reach land to waves and currents, as well as to changes in storm characteristics also driven by climate change.

Global sea-level rise is one of the more certain impacts of human induced global warming. Given the large and growing concentration of population and economic activity in the coastal zone of New Jersey, as well as the importance of its coastal ecosystems, the potential impacts of sea-level rise have elicited widespread concern. To understand sea-level change, we must know the sum of global, regional and local trends related to changing ocean and land levels.

Global sea-level rise is the result of an increase in the ocean volume, which evolves from changes in ocean mass due to melting of continental glaciers and ice sheets, and expansion of ocean water as it warms. Regional sea-level trends include land subsidence or uplift due to geological processes, the influence of ocean currents and gravity. At a local scale the amount of ground water withdrawal and tidal range variation may be important.

The sum of global, regional and local trends leads to certain areas of the Earth having far greater rates of sea-level rise. One of these hotspots is New Jersey!

Unfortunately, even a small increase in sea-level rise can have devastating effects on coastal habitats. As seawater reaches farther inland, it can cause destructive erosion, contamination of aquifers and agricultural soils, and lost habitat for fish, birds, and plants.  When large storms hit land, higher sea levels mean bigger, more powerful storm surges. Higher sea levels would force people to abandon their homes and relocate. Low-lying regions could be submerged completely.

Dr. Ben Horton, professor in the Department of Marine and Coastal Sciences, teaching about climate change.PHOTO PROVIDED

3. What do the scientists hope to have happen, in a best case scenario? Given that there's clearly no "going back" what is their benchmark for "success," or what constitutes a positive outcome for them? Is it a slowing down the onset of the bad stuff, or lessening the severity, or both?

Rutgers has just published projections of sea-level rise for 2100. If we do nothing to limit greenhouse gas emissions sea-level could rise by as much 1.3m. But if we reduce our emissions sea-level rise may be less than 60 cm. That is a big difference! To provide context the 20 cm sea-level rise in NYC during the 20th century meant the storm surge from Hurricane Sandy affected 11.4% more people, 11.6% more housing units, and caused $2 billion in additional damage than it would have without sea-level rise

4. What can one person do? 100 people do? What can people in one specific geographical (or political) region do? Is the best plan of action to drive less (for example), or to do something good for a specific river (for example), or to organize to elect an official at a certain level of government who can represent a climate change-centered agenda? Speaking of which, at what level of government or policy does this all take place? I've always assumed that,because of the scope, it was federal — but maybe this is incorrect?

Science may be able to inform policy by forecasting how severe climate change will be. However, when confronting environmental challenges, considerations of fairness, equity, and justice must also inform international agreement to combat climate change.

To combat climate change we must have multiple solutions and implementing just a few of them could make a difference. We must forego fossil fuels and alongside this upgrade our infrastructure, dramatically curtail transportation fuel needs, consume less, be much more efficient. On an individual level we can:

• Turn off the lights when you leave a room.

• Turn off your computer and other electronic devices when you're not using them.

• Drive less. Instead, walk, ride your bike, or use public transportation if you can.

• Use less water.

• Create less waste.

• Recycle used paper, cans, bottles, and other materials.

5. I'm hearing all of this craziness about the legitimacy of scientists being under attack, and scientists being concerned about the security of their funding, resources, and data. Is there anything that I can do to support them? Should I call a representative? Donate to an organization? Is there an organization or watchgroup that keeps on top of certain threats of this kind that would be particularly good to pay attention to?

Science provides the foundation for policies, actions, and decisions made on behalf of the American people. Climate science has stringent scientific peer review processes that are designed to ensure that all decisions are founded on credible science and data.

Unfortunately science appears to be under attack, and public trust in key scientific theories has been eroded from climate change to vaccinations. Empowered by their own sources of information and their own interpretations of research, doubters have declared war on the consensus of experts. In 2013 and 2014 over 69,000 scientists published on climate change. Only 4 rejected that climate change was caused by human activity! But only 40 percent of Americans, according to the most recent poll from the Pew Research Center, accept that human activity is the dominant cause of global warming.

About Meg McGuire

Meg McGuire has been a journalist for 30 years in New York and Connecticut. She started in weekly newspapers and moved to full-time work in dailies 25 years ago. She knows about the tectonic changes in journalism firsthand, having been part of what was euphemistically called a "reduction in force" six years ago. Now she's working to find new ways to "do" the news as an independent online publisher of news about the Delaware River, its watershed and its people.

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