Category: Global Warming

The “Perfect Storm” caused the maxi coral bleaching
The “Perfect Storm” caused the maxi coral bleaching

The “perfect storm” caused by “unprecedented climatic conditions“. This is how a group of researchers defined what caused the big bleaching of the Great Barrier Reef.

El Nino and higher temperatures have always been known to be the main causes of coral bleaching. To these two facts, now researchers added that warmer water temperatures can result in coral bleaching. Why? Well, when water is too warm, corals expel the algae living in their tissues causing the coral to turn completely white. This is called coral bleaching. When a coral bleaches, it is not dead. Corals can survive a bleaching event, but they are under more stress and are subject to mortality.

Coral bleaching on the Great Barrier Reef from GBRMPA on Vimeo.

The 2016 El Nino warmed the water near the  Gulf of Carpentaria: here water was 34°C! That’s very warm, too warm! This extremely hot water, moved towards the northern part of the Great Barrier Reef where it stopped. Warmer than usual water then stayed in this area, putting corals under a lot of stress. The majority ( 70%) of the corals died north to Port Douglas: that’s the 29% of the corals in the Great Barrier Reef.

So global warming is rapidly emerging as a universal threat to ecological integrity and function, highlighting the urgent need for a better understanding of the impact of heat exposure on the resilience of ecosystems and the people who depend on them.

Global warming and the role of Oceans
Global warming and the role of Oceans

Oceans play an important role for the health of our Planet because they can slow down global warming. In the last 6 years the cabon dioxide emissions, due to human activities, and the 90% of the global warming due to greenhouse effect, have been absorbed by the oceans. They’re like a big spunge that absorbs heat, carbon dioxide and other gases for decades or even centuries. NASA and MIT scientists discovered that gases are more easily absorbed over time than heat energy.  In some cases oceanic currents were even slowing down beacuse of the addition of heat.

They simulated the flow of one of the most important parts of the Atlantic Meridional Overturning Circulation, the Gulf Stream that carries warm water from Florida to Greenland where it cools and sinks to 1000 meters (about 3281 feet) or more before traveling back down the coast to the tropics. On its northward journey, the water at the surface absorbs gases like carbon dioxide as well as excess heat from the atmosphere. When it sinks near Greenland, those dissolved gases and heat energy are effectively buried in the ocean for years to decades and longer. Removed from the atmosphere by the ocean, the impact of their warming on the climate has been dramatically reduced.

Climate change and oceans: what about the future?

The positive effect oceans have today over global warming, could turn out to be a problem in the future. One day, hundred years into the future, oceans will put back into the atmosphere the gases and heat buried. The ocean recirculates and, at some point, will release some of it back to the atmosphere, where it will keep raising temperatures. This eventual release of buried gases and heat from the oceans is sometimes called the “warming in the pipeline”.

In April the Arctic sea ice nearly set a new record
In April the Arctic sea ice nearly set a new record

Bad news form the North Pole. The Arctic sea ice extent was 980,000 square kilometers (378,400 square miles) below the average and only 20,000 square kilometers (7,700 square miles) above the record low April extent set in 2016. Sea ice in the Arctic expands and shrinks following the seasons: in summer the ice extent reaches its minimum, in winter its maximum size. During the month of April the ice starts to melt but usually not this much. Arctic sea ice extent for April 2018 averaged 13.71 million square kilometers (5.29 million square miles). Just to give an idea, the ice surface missing is 3 times the size of Italy! Only in April 2016 the situation was worse that today with 20.000 square kilometers more missing.

The endangered Mediterranean species
The endangered Mediterranean species

Up to half of plant and animal species in the world’s most naturally rich areas (like the Amazon, the Arctic, the Galapagos, the Mediterranean and the Black Sea Basin) could face local extinction by the turn of the century due to climate change. This is what WWF fears on the basis of a research published on the Climatic Change journal in which are examined the impacts of climate change on nearly 80,000 plant and animal species in 35 of the world’s most diverse and naturally wildlife-rich areas. Nearly 30% of Mediterranean species like marine turtles and tuna are at risk of extinction even if we keep global warming to 2°C; this rises to 50% with no action at all.

The Mediterranean is among the areas most exposed to climate change. High temperatures in the future will rapidly exceed those experienced in the recent years, leading to dangerous heat stresses on natural and human systems. Increasing sea and sand temperatures are expected to disrupt and severely threaten the survival of the most marine species like marine turtles, cetaceans, bluefin tuna, whales and sharks. This will happen in a marine ecosystem already put under pressure from rampant overfishing, unsustainable tourism and energy and transport developments. We urgently need to shift to sustainable energy and economic models in order to protect our ocean and our livelihood.

Arctic Ocean is getting more acidic: what does it mean?
Arctic Ocean is getting more acidic: what does it mean?

The Arctic Ocean is not only getting warmer but even more acidic. An international research team for Nature Climate Change found a rapid rise in acidification in the western Arctic Ocean.
Why? What could be the consequences? Let’s try to understand this phenomenon.

In this study, researchers from all over the world analyzed ocean acidification of the Arctic Ocean and compared the results with the historical data from 1990 to 2010. In only 15 years acidified waters have expanded north about 300 nautical miles from Alaska to just below the North Pole and not just on the sea surface: the depth of acidified waters was found to have increased, from approximately 325 feet to over 800 feet (or from 100 to 250 meters).

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Why is water acidifying?

Acidification is becoming a big problem all over the world, due to climate change. Carbon dioxide (CO2) in the atmosphere is growing and it is absorbed by seawater where chemical reactions occur that reduce seawater pH, carbonate ion concentration, and saturation states of biologically important calcium carbonate minerals. One fourth of the carbon dioxide floating in the atmosphere is absorbed by water. These chemical reactions are termed “ocean acidification” or “OA” for short.

What are the consequences?

Ocean Acidification is a potential threat to shellfish, the marine ecosystem and the fishing industry.

Calcium carbonate minerals are the building blocks for the skeletons and shells of many marine organisms. In areas where most life now congregates in the ocean, the seawater is supersaturated with respect to calcium carbonate minerals. This means there are abundant building blocks for calcifying organisms to build their skeletons and shells. However, continued ocean acidification is causing many parts of the ocean to become undersaturated with these minerals, which is likely to affect the ability of some organisms to produce and maintain their shells.

 

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The Sahara Desert got bigger
The Sahara Desert got bigger

Climate changes in the last century caused the expansion of the world’s biggest desert, the Sahara. According to a study published on the Journal of Climate the Sahara Desert has grown by 10 percent over the last century due to a combination of natural climate variations and global warming.

The growth of the Sahara has been influenced by the Atlantic Multidecadal Oscillation, a natural climate cycle that changes the Atlantic Ocean from warm to cold phases every 60 to 80 years and can impact rainfall patterns across much of Africa. Also global warming may also be altering atmospheric circulation patterns, such as the Hadley cell, which moves air from the Equator to the subtropics, drying it out as it goes and creating many subtropical deserts, including the Sahara.

Researchers estimate that around one third of the Sahara’s expansion is down to climate change caused by human activity. That has implications for those who live in the Sahara as well as the wider world.

Five questions on global warming
Five questions on global warming

Earth is warming up—and fast.

The average climate reported throughout the entire planet is called “Global Climate”. Scientists and all of us are very concerned because global climate is changing. The earth’s average temperature is rising – and faster that in any other period scientists have studied in earth’s history.

What’s “climate”?

“Climate” describes weather over a long period and in large regions.

Climate is the big picture of temperatures, rainfall, wind and other conditions over a larger region and a longer time than weather. For example, the weather describes a specific situation  for example it was rainy in Phoenix, Arizona, last week. But rainfall in this city is only about 7 inches per year. So the climate for Arizona is dry. Much of Southern California and North Africa also have a dry, desert climate. Brazil and regions of Southeast Asia have a tropical climate, because it’s warm and rains there a lot.

Weather is local and temporary.

Wouldn’t it be great if we could control Earth’s temperature with a thermostat like at home? Not possible! The most we can do is predict what the weather will be like in the next few days. The scientists who study the weather are called meteorologists and they are the ones that try to foresee what  is going to happen next. Will a storm over the ocean turn into a destructive hurricane? What about that giant cloud over London? Will it rain there or go to Dover before letting loose? Tornado conditions are just right, will any form? and where?

Weather events like snow, rain, wind, hail are local and temporary

Should we care if Earth is getting warmer?

Yes, after all, Earth is our spaceship.

It is a self-containing vessel that has all the air, water, and food we needand it carries us on a 938-million-kilometere cruise around the Sun every year, and not only! The earth has its own magnetic field that protects us from killer radiation and brutal solar wind.

We should consider ourselves like  astronauts on a long space voyage, we have to check and control our “ship’s” vital functions and keep our Earth a healthy place to live in.

Does whatever we do matter much?

Yes! Everything that happens in one place affects something in another.

Earth has its own regulation system. The oceans, the land, the air, the plants and animals, and the energy from the Sun all work together in harmony.  Changes in one place can affect things in another faraway place. The total effect is our global climate.

What is making Earth’s climate warmer?

Why is Earth getting warmer?

Human activity is one of the causes, scientists say.

How did they find that out? How could we be changing the global climate? How could it change so fast? What is going to happen to people, animals and plants if the earth gets warmer? Can we do anything to stop global warming or slow it down?