The lithosphere participates in the climate system chiefly through
Answer: A
Silicate weathering removes carbon dioxide over millions of years and volcanism returns it, which sets the very long term background. On human timescales its role is largely static. Volcanism returns what weathering removes.
Please log in or register to report this question.
Assertion (A): The lithosphere matters for climate on geological timescales but not on decadal ones.
Reason (R): Weathering and volcanism operate over millions of years.
Answer: B
Both are true and the reason gives the timescale, and it is why the slow carbon cycle is left out of models used to project the coming century. Millions of years is its timescale. The fast carbon cycle is a quite separate matter.
Please log in or register to report this question.
Arrange the components of the climate system in order of increasing response time.
1. the deep ocean
2. the atmosphere
3. the large ice sheets
4. the ocean mixed layer
Answer: C
Correct answer: 2 - 4 - 1 - 3
The order follows heat capacity and mixing rate: the atmosphere responds in days, the ocean mixed layer in months to years, the deep ocean over centuries, and the ice sheets over millennia. The practical consequence is that the system responds to a forcing on many timescales at once, so the warming already committed by past emissions continues long after the emissions themselves change.
Please log in or register to report this question.
The biosphere affects climate through
Answer: D
Photosynthesis and respiration drive the fast carbon cycle, and vegetation changes both albedo and evaporation. The land surface is one of the more difficult parts of a climate model to get right. Albedo and transpiration both matter.
Please log in or register to report this question.
State whether the following is true or false.
Vegetation influences climate through albedo and evapotranspiration as well as through carbon.
Answer: A
A forest is darker and transpires more than grassland, so replacing one with the other changes both the energy and the water balance. These effects can rival the carbon effect locally. Land cover change acts through both.
Please log in or register to report this question.
Consider the following statements about coupling in the climate system.
1. The components exchange energy, momentum and matter.
2. A change in one component propagates to the others.
3. Each component can be modelled in isolation without loss.
Answer: B
The first two are correct. The third is the reason coupled models exist, since an atmosphere model with a fixed ocean gives a quite different answer from a coupled one. Coupling is essential. Each component responds to what the others do.
Please log in or register to report this question.
Climate sensitivity is usually defined as the equilibrium warming for
Answer: C
It is a convenient benchmark that packages the net effect of all the feedbacks into a single number. Its uncertainty is dominated by the cloud feedback. It packages every feedback into one figure. Doubling is the conventional benchmark used.
Please log in or register to report this question.
From the list given below, identify the organism type in the biological pump that takes up carbon dioxide from the atmosphere into the ocean.
GATE XE - 2023,
Answer: C
The organisms are Phytoplankton.
The biological pump begins with photosynthesis. Phytoplankton in the sunlit surface layer fix dissolved CO2 into organic matter, which lowers the surface water's CO2 and lets more be drawn in from the atmosphere. Part of that carbon then sinks to depth as dead cells, faecal pellets and aggregates.
Zooplankton, fish and radiolarians feed on and repackage that organic carbon, and help move it downward, but they respire CO2 rather than taking it up from the air. They are consumers in the pump, not the primary producers that draw CO2 in.
Please log in or register to report this question.
