You said FALSE. You are correct! Changes in tropical storm intensity and frequency are dominated by interdecadal variations. No clear evidence for changes in tropical storm activities over the 20th century exist so far.

Due to incomplete data and limited analysis it is not clear if there have been long-term changes in extra-tropical cyclones. In the northern hemisphere, regional increases have been identified (e.g. in Europe over the past several decades), whereas in the southern hemisphere it is possible that there has been a decrease in extra-tropical cyclone activity since the 1970s.

You said TRUE. The correct answer is FALSE. Because tornadoes and other small-scale severe weather phenomena (e.g. hail, lightning, thunder days) are characterized by random temporal and spatial events, it is not possible to measure all such events. There have been relatively few large-scale analyses of these events so far. Nevertheless, recent analyses of changes in severe local weather in a few regions provide no compelling evidence for systematic long-term changes.

You said FALSE.

You are correct! Because tornadoes and other small-scale severe weather phenomena (e.g. hail, lightning, thunder days) are characterized by random temporal and spatial events, it is not possible to measure all such events. There have been relatively few large-scale analyses of these events so far. Nevertheless recent analyses of changes in severe local weather in a few regions provide no compelling evidence for systematic long-term changes.

Incorrect. The correct answer is FALSE. It is correct that there have been very likely decreases in the extent of the snow cover since the late 1960s, but the situation is not as dramatic as mentioned in this statement: Satellite data show that there have been decreases of about 10% in the extent of snow cover. Moreover, during the 20th century there has been a probable reduction of about two weeks in the annual duration of lake- and river ice cover in the northern hemisphere and about a 40% decline in Arctic sea ice thickness during late summer in recent decades.

Congratulations! It is correct that there have been very likely decreases in the extent of the snow cover since the late 1960s, but the situation is not as dramatic as mentioned in this statement: Satellite data show that there have been decreases of about 10% in the extent of snow cover. Moreover, during the 20th century there has been a probable reduction of about two weeks in the annual duration of lake- and river ice cover in the northern hemisphere and about a 40% decline in Arctic sea ice thickness during late summer in recent decades.

Correct. Recent analyses indicate that permafrost in many regions of the world is recessing. For example, in North America teh southern boundary of the discontinuous permafrost zone has shifted northwards in response to climate change after 1850, and in China a shrinking of the permafrost extent has been recorded.

Sorry. Your answer is incorrect. Recent analyses indicate that permafrost in many regions of the world is recessing. For example, in North America teh southern boundary of the discontinuous permafrost zone has shifted northwards in response to climate change after 1850, and in China a shrinking of the permafrost extent has been recorded.

Correct. A widespread retreat of glaciers in non-polar regions can be recorded during the 20th century. A few exceptions in coastal regions are consistent with atmospheric circulation variations and related precipitation increases. See the example in the Swiss Alps.

You answered FALSE. This is incorrect. A widespread retreat of glaciers in non-polar regions can be recorded during the 20th century. A few exceptions in coastal regions are consistent with atmospheric circulation variations and related precipitation increases. See the example in the Swiss Alps.

Incorrect. This statement is untrue. Total atmospheric water vapour has increased over many regions of the Northern Hemisphere and it's very likely that precipitations have increased over most mid- and high latitudes of the Northern Hemisphere continents as well as (less obviously) over the tropical land areas (10�N to 10�s). There has also bee an increase in teh frequency of heavy precipitation events in the mid- and high latitudes of teh Northern Hemisphere. But it is also likely that precipitations have decreased over the Northern Hemisphere subtropical land areas (10�N to 30�N) and no systematic changes in precipitations have bee detected over the subtropical-mid- and high latitudes of teh Southern Hemisphere.

Yes. It this is FALSE. This statement is untrue. Total atmospheric water vapour has increased over many regions of the Northern Hemisphere and it's very likely that precipitations have increased over most mid- and high latitudes of the Northern Hemisphere continents as well as (less obviously) over the tropical land areas (10�N to 10�s). There has also bee an increase in teh frequency of heavy precipitation events in the mid- and high latitudes of teh Northern Hemisphere. But it is also likely that precipitations have decreased over the Northern Hemisphere subtropical land areas (10�N to 30�N) and no systematic changes in precipitations have bee detected over the subtropical-mid- and high latitudes of teh Southern Hemisphere.

Well done. This statement is true. Melting glaciers cause an increase in water running in to the sea and the increase in sea temperatures causes an expansion of sea water volumes (eustatic sea water level fluctuations). But sea level is also influenced by processes that are not directly related to climate change, such as terrestial water storage, (e.g. extraction of ground water, changes in surface runoff) or geological processes (e.g. slow processes in the Earth's crust like isostasy).

Incorrect. This statement is in fact true. Melting glaciers cause an increase in water running in to the sea and the increase in sea temperatures causes an expansion of sea water volumes (eustatic sea water level fluctuations). But sea level is also influenced by processes that are not directly related to climate change, such as terrestial water storage, (e.g. extraction of ground water, changes in surface runoff) or geological processes (e.g. slow processes in the Earth's crust like isostasy).

Correct. This is true. Since 1978, the period of satellite measurements, no significant trends of Antarctic sea ice extent can be detected. Moreover, some parts of Antarctica have not warmed in recent decades as neither have some parts of the southern hemisphere oceans.

You said FALSE. The correct answer is TRUE. Since 1978, the period of satellite measurements, no significant trends of Antarctic sea ice extent can be detected. Moreover, some parts of Antarctica have not warmed in recent decades as neither have some parts of the southern hemisphere oceans.