Changing salinity, along with rising water temperature, may disrupt the currents. In an extreme case, thermohaline circulation could be disrupted or even shut down in some parts of the ocean, which could have large effects on climate. Some climate scientists believe that hurricanes, typhoons, and other tropical cyclones will change as a result of global warming.
Warm ocean surface waters provide the energy that drives these immense storms. Warmer oceans in the future are expected to cause the intensification of such storms. Although there may not be more tropical cyclones worldwide in the future, some scientists believe there will be a higher proportion of the most powerful and destructive storms.
Some scientists believe we already see evidence for an upswing in the numbers of the most powerful storms. Others are less convinced. Clouds are a bit of a wild card in global climate models.
Warmer global temperatures produce faster overall evaporation rates, resulting in more water vapor in the atmosphere Different types of clouds at different locations have different effects on climate. Some shade the Earth, cooling the climate. Others enhance the greenhouse effect with their heat-trapping water vapor and droplets.
Scientists expect a warmer world to be a cloudier one, but are not yet certain how the increased cloudiness will feed back into the climate system. Modeling the influence of clouds in the climate system is an area of active scientific research. Ocean ecosystems will change as sea-surface temperatures continues to warm.
Animals like fish are able to move to other ecosystems with cooler water at higher latitudes. Warmer waters in the shallow oceans have contributed to the death of about a quarter of the world's coral reefs in the last few decades. Many of the coral animals died after being weakened by bleaching, a process tied to warmed waters. Changes in temperature, precipitation, and seasonal timing will alter the geographic ranges of many types of plants and animals.
Since species can only survive if they are in a habitat that suits their needs, many species will face extinction if the geographic range where they can survive shrinks. However, if we can keep the amount of warming to 1. On the other hand, the range of some species, such as mosquitos which carry different types of diseases, may increase due to climate warming. Warming surface temperatures are also predicted to increase the frequency of heat waves and droughts, which can affect crop production, increase the risk of wildfires, and even impact human health.
Climate change is causing many other aspects of Earth to change, including the examples noted in this graphic. Many major cities, including Hong Kong, Rio de Janeiro and Miami, are already flooded and uninhabitable. The Maldives, the Marshall Islands, Tuvalu and many other small island nations have been abandoned. Many coastal and river areas are regularly flooded , including the Nile Delta, the Rhine valley and Thailand.
Winter storms are more energetic and unleash more water, causing widespread wind damage and flooding each year. Tropical cyclones have become stronger and affect tens of millions of people every year. South-east Asian monsoons have become more intense and unpredictable, bringing either too much or too little rain to each region, affecting the lives of over three billion people. Food and water insecurity has increased around the world, threatening the health and wellbeing of billions of people.
Extreme heat and humidity in the tropics and subtropics has increased the number of days that it is impossible to work outside tenfold — slashing farm productivity. Extreme weather in temperate regions like Europe has made food production highly unpredictable. Half of the land devoted to agriculture in the past is now unusable, and the capacity of the rest to grow food differs widely from season to season. Crop yields are at their lowest levels since the middle of the 20th century.
Fish stocks have collapsed. The ocean food chain has collapsed in some regions as the small marine organisms that form its base struggle to make calcium carbonate shells and so survive in the more acidic waters. Despite advances in medical sciences, deaths from tuberculosis, malaria, cholera, diarrhoea and respiratory illnesses are at their highest levels in human history.
Extreme weather events — from heat waves and droughts to storms and floods — are causing large loss of life and leaving millions of people homeless. Disease epidemics have plagued the century, spreading among populations beleaguered by widespread poverty and vulnerability.
This is what our planet could look like if we do everything in our power to contain climate change. Lingering remnants of our fossil fuel emissions may still warm the atmosphere enough then to prevent the ice age from occurring.
Fortunately, long-term perspectives may also suggest possible win-win situations, as well. For instance, leaving most remaining coal untouched rather than using it all up now would reduce the severity of climate change in the near-term, and would also leave large stores of burnable carbon in the ground that later generations could use as a source of greenhouse gases for the prevention of future ice ages, should they so desire. Whichever emissions scenario we choose-be it moderate or extreme-one thing is now clear.
Our influence on the climatic future of the world is geological in scope. Figure 6 The rubble-strewn snout of a glacier in southern Iceland, with people in the background for scale.
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Modeling Sea Level Rise.
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