Evidence for Present Climate Change Flashcards
What are the measurable indicators that show climatic warming?
The measurable indicators that unequivocally show climatic warming:
- Increasing temperatures over land and ocean surfaces, and in the troposphere
- Increasing sea-surface temperatures and ocean heat content
- Melting glacial ice and sea ice
- Rising sea level
- Increasing humidity
How many decades have been successively warmer on earth?
• Each of the past three decades has been successively warmer at the Earth’s surface than any preceding decade since 1850.
What type of warming dominates the increase in energy stored in the climate system?
• Ocean warming dominates the increase in energy stored in the climate system, accounting for more than 90% of the energy accumulated between 1971 and 2010. Further uptake of carbon by the ocean will increase ocean acidification.
What has been occurring over the last two decades to the Greenland and Antarctic Ice sheets?
• Over the past two decades, the Greenland and Antarctic ice sheets have been losing mass, glaciers have continued to shrink almost worldwide, and Arctic sea ice and Northern Hemisphere spring snow cover have continued to decrease in extent.
How much has the mean sea level risen over the period of 19-01 - 2010?
• The rate of sea-level rise since the mid-19th century has been larger than the mean rate during the previous two millennia. Over the period 1901–2010, global mean sea level rose by 0.19 m.
What dose modern temperature data tell us about temperatures on earth sense 1880
The temperature data unmistakably show a warming trend. Since 1880, in the Northern Hemisphere, the years with the warmest land-surface temperatures were 2005 and 2010 (a statistical tie). For the Southern Hemisphere, 2009 was the warmest in the modern record. In Chapter 5, we saw that the period from 2000 to 2010 was the warmest decade since 1880
How much has recent Ocean temperatures risen?
Ocean temperatures are also rising. As discussed in Chapter 5, sea-surface temperatures increased at an average rate of 0.07 C° per year from 1901 to 2012 as oceans absorbed atmospheric heat.
What forms of Land Ice are there? Where can they be found? What effects dose earths rising temperatures have on them?
Land ice occurs in the form of glaciers, ice sheets, ice caps, ice fields, and frozen ground. These freshwater ice masses are found at high latitudes and worldwide at high elevations. As temperatures rise in Earth’s atmosphere, glaciers are losing mass, shrinking in size in a process known as “glacial retreat”
How much has summer melt on Greenland’s Ice sheet increased in recent history?
Summer melt on the Greenland Ice Sheet increased 30% from 1979 to 2006, with about half the surface area of the ice sheet experiencing some melting on average during the summer months. In July 2012, satellite data showed that 97% of the ice sheet’s surface was melting, the greatest extent in the 30-year record of satellite measurements.
How much of the Artic permafrost do scientists estimate will thaw over the next 200 years?
Scientists now estimate that between one- and two-thirds of Arctic permafrost will thaw over the next 200 years, if not sooner; these permafrost reserves took tens of thousands of years to form. Warming land and ocean temperatures may also cause the thaw of methane hydrates stored in permafrost and in deep-ocean sediments on the seafloor
What is Sea ice (Pack ice) and how dose it effect global albedo?
Sea ice is composed of frozen seawater, which forms over the ocean. (Sea ice does not include ice shelves and icebergs, which are made up of freshwater originating on land.) Arctic sea ice, also called pack ice, is especially important for global climate owing to its effects on global albedo; remember that the Arctic region is an ocean surrounded by landmasses, and sea ice in this region helps cool the planet by reflecting sunlight.
What are current/recent trends in Sea Ice throughout the year?
Every summer, some amount of sea ice thaws; in winter, the ice refreezes. Satellite data show that the summer sea-ice minimum extent (occurring in September) and winter sea-ice maximum extent (occurring in February or early March) have declined since 1979
What are the trends in September sea ice in the Artic ocean?
September sea ice is declining at a rate of 11% per decade (compared to the 1979–2000 average) and reached its lowest extent in the modern record in 2012 (Figure 11.20b). The accelerating decline of summer sea ice, resulting in record low levels of sea ice in 2012 and 2016, suggests that summer sea ice may disappear sooner than predicted by most models; some scientists estimate an ice-free summer Arctic Ocean within the next few decades.
What have scientists noted is recently occurring to multiyear ice?
As evidence of accelerating losses of Arctic sea ice, scientists have recently noted a decline in multiyear ice, the oldest and thickest ice, having survived through two or more summers. Younger, thinner, seasonal ice forms over one winter and typically melts rapidly the following summer.
What is the domino effect that the decline of multiyear ice causes?
Scientists think that the decline of multiyear ice causes an overall thinning of the Arctic pack ice that thus becomes vulnerable for further, accelerating melt. In addition, as the season for ice formation becomes shorter, multiyear ice cannot be replaced. Only a persistent cold spell would enable multiyear ice to form and reverse the current trend.
