It's important to understand that both humanitarians and climatologists are ultimately working towards the betterment of humanity and the planet. Their goals may appear to be different, but they often complement each other. Humanitarians aim to improve the quality of life for people, while climatologists strive to understand and mitigate the impacts of climate change. A sustainable and prosperous future requires addressing both human welfare and environmental concerns.

In the Venn diagram of these two groups, the overlapping area might involve efforts to create sustainable development, reduce poverty, and address social injustices while simultaneously addressing climate change. For instance, both groups might advocate for:

• Renewable energy sources to reduce greenhouse gas emissions and improve energy access for impoverished communities.
• Sustainable agricultural practices to improve food security, conserve water resources, and protect ecosystems.
• Population control measures through education and access to birth control, leading to a stable global population and reduced stress on natural resources.

It is difficult to say exactly what the world population would be without modern medicine, technology, supply chains, and charity. However, it is likely that the population would be much smaller than it is today.

Without modern medicine, many people would die from diseases that are now easily treatable, such as pneumonia, malaria, and tuberculosis. Without technology, such as irrigation and fertilizers, food production would be much lower, leading to widespread hunger and malnutrition. Without supply chains, it would be difficult to transport food and other essential goods to people who need them, leading to even more deaths. And without charity, many people would not have access to the basic necessities of life, such as food, water, and shelter.

All of these factors would contribute to a much lower world population. Some estimates suggest that the population would be as low as 1 billion people. However, it is also possible that the population would be higher, if people were able to adapt to the challenges of living without modern technology and medicine.

The idea that the human population needs to collapse to ensure the survival of humanity is a controversial and highly debated one. There are several factors and perspectives to consider.

1. Environmental impact: Overpopulation and the resulting overconsumption of resources have led to concerns about the planet's ability to sustain the current human population. Deforestation, pollution, loss of biodiversity, and climate change are some of the major problems. To address these issues, some argue that reducing the population would decrease the demand for resources and mitigate environmental degradation.
2. Resource scarcity: With the increasing demand for water, food, and energy, resource scarcity is a growing concern. However, many experts argue that better resource management, technological advancements, and sustainable practices can help address these challenges without requiring a population collapse.
3. Social and economic factors: High population growth can lead to challenges such as poverty, unemployment, and social unrest. However, the relationship between population and economic development is complex, and other factors such as governance, education, and infrastructure play critical roles. Developing policies and strategies to address these issues may help alleviate the negative consequences of population growth.
4. Population control measures: Population collapse is not the only solution for addressing overpopulation. Measures such as family planning, access to contraceptives, education, and empowerment of women have proven effective in reducing population growth rates in various countries.