There are two main reasons why winter layers are darker than summer layers in ice cores.

• The snow that falls in the winter is typically more polluted than the snow that falls in the summer. This is because there is more dust and other pollutants in the air during the winter months, when the weather is colder and there is less wind to disperse them. When this polluted snow falls, it mixes with the existing snow on the ground, making the layers darker.
• The snow that falls in the winter is also typically more compacted than the snow that falls in the summer. This is because there is less melting and refreezing in the winter, which allows the snow to pack down more tightly. The more compacted the snow, the darker it appears.

The regularity of droughts is likely to be affected by climate change in a number of ways.

• Warmer temperatures are likely to lead to more evaporation, which could lead to drier conditions.
• Changes in precipitation patterns could also lead to more droughts. For example, a shift from a wet climate to a drier climate could lead to more droughts.
• The melting of glaciers and ice sheets could also contribute to droughts. This is because glaciers and ice sheets store a large amount of water, and their melting could release this water into the atmosphere, which could lead to more evaporation and drier conditions.

It is important to note that the relationship between climate change and droughts is complex and there is still much that we do not know. However, the evidence suggests that climate change is likely to make droughts more frequent and severe in many parts of the world.

Here are some additional things to consider:

• Droughts are not just caused by climate change. Other factors, such as natural variability and human activities, can also play a role.
• The effects of climate change on droughts will vary from region to region. Some areas may become more prone to drought, while others may become less so.
• It is important to take steps to adapt to the effects of climate change, such as developing drought-resistant crops and improving water conservation measures.

Dr Murtadha Shukur thank you for your contribution to the discussion