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Using pollen as a natural hygroscopic material instead of harmful chemicals to act as a cloud condensation nuclei for rain enhancement.



Using the conventional methods in cloud seeding including the chemicals such as silver iodide, potassium iodide and dry ice (solid carbon dioxide) and salt like NaCl and CaCl2 can effect negatively on the environment. For example, Silver iodine may cause ’Iodism’, a type of iodine poisoning where the patient exhibits running nose, headache, skin rash, anemia etc. And using salts requires large quantities that increases the salinity of soil and water. Such materials are also expensive and require huge investments. Using naturally available sources can prevent the negative impact of the process on the environment, on humans and other creatures while also reducing the total cost of the process. One option is to use the pollen grains, they are produced by flowering flora that deliver the male gametes that pollinate female plants. Their size (diameter) varies between 10 and 100 mm. They can be lifted in the atmosphere to altitude up to 3000 m and higher, and they can stay there for long times. Pollen have strong outside wall resistance and that makes them insensitive to external influences. They also, have hygroscopic characteristics which enable them to build up a water layer from a humid environment not only at their surface but also into their interior by capillary effects.



In UAE this method can be employed by using pollen from grass and different trees. The Idea can be implemented by first conducting research on the best plants for pollen grains that can be used in this process. Such plants must be able to grow in UAE environment and their pollen grains must be suitable for rain enhancement. The plants can be seasonal where in summer it can be used in seeding the relative high humid areas and in winter can be used in the low cloud area. This method can help in reducing the cost of rain enhancement dramatically, and will help in increasing the green cover of the country. 

Category of the action

Mitigation/Adaptation, Changing public attitudes about climate change

What actions do you propose?


Additional summary:

Pollen are large biological aerosol particles with a diameter of 10 -100 um. The low sink velocities grains can be lifted in atmosphere to altitudes up to 3000 m and higher and they can stay there for long times. Under high humidity or moist conditions, the pollen grains can repute and expel cytoplasmic material, forming smaller particles (sub pollen particles - SPP) those particles are additional source of organic carbon to the atmosphere. The SPP can act as a cloud condensation nuclei (CCN) that open the door for new pathway for coupling the vegetation-climate feedback. Since the grains can take up significant amount of water from a humid environment not only the surface but also the interior by capillary effect; then they have the ability to act as the conventional materials used in the world currently. According to (Steiner, 2015) depending on land cover and meteorological conditions, atmospheric pollen counts reach up to several thousand grains per cubic meter of air during peak pollination season.  In some locations, peak spring pollen counts reach up 6000–12,000?grains?m3 depends on the type. Using observed pollen counts from the atmospheric surface layer, the formation of 105–106 SPP per grain would be needed to provide a substantial contribution to CCN (100 to 1000?cm3) in the atmosphere.

There are many different types of pollen grains that can be used apart from common grasses. The widely tested plants whose pollen is suitable for cloud seeding are Pine and Oak. Interestingly, although these plants may not grow in desert areas naturally, but they are very well adaptable to desert conditions. They have a general water requirement of 20 gallons/ day/ plant in the growth stage which gradually reduces as the plant grows in to a tree. Some estimates show that about 1010 – 1012 pollen grains are emitted per tree annually out of which 1% are directly lofted in the atmospheric in some regions (Steiner 2015). While there may be high uncertainties with this option, it is however a major area where action is needed to organize the plantation in a way that leads to rain enhancement.

In UAE there are plenty of plants that can live and grow in the environment. One example of a plant that produces pollen but does not need fresh water for growth is the Mangrove (Avicenna marina). Mangrove pollen has been used in many places for different purposes, however not analyzed for its rain enhancement capabilities. They grow in a modest temperature of not more than 35°C and low salinity water. Within the UAE there are approx. 3000 hectares of mangrove forest (of which 2300 hectares are found in Abu Dhabi). Mangroves provide home and safe breeding ground for some fish species, turtles and commercially significant shrimp, snapper, grunt fish & sea bream and of course they offer a safe haven for bird nesting, migration & egg laying.  They also can help in the prevention of coastline erosion caused by wave action and ocean currents. They also reduce the health related problems of pollen by avoiding growth of more pollen plants in lieu of the fact that UAE has high aerosol concentrations. However if plants must be grown after all, the primary solution to minimize the health risks would be chose a location that is less probable to contaminate the city air with pollen.

Action plan:

The action plan for this idea involves multiple components that are equal in importance and collectively responsible for successful implementation. These components are successive although at later stages of the project timeline there may be a need for parallel implementation of multiple action plan components. Further detailed description is given below:

Action Plan Component – 1: Review, Research and Development

The first step to begin the project would be to start from reviewing the existing technologies and materials that are currently being used globally, and specifically in UAE for rain enhancement through cloud seeding. This review will help build a strong property list as well as practical data information to facilitate in choosing the right pollen material that will suitably replace the conventional materials. The following step would be to review all the available options of pollen material to substantiate the need. This will lead to research and development in basically the chemical and material fields for optimizing the pollen for the purpose. This research will be carried out by graduate students and researchers of a local UAE university, and it could involve both computational and experimental research. Upon achieving the research targets related to the suitable pollen grains, will then be the development stage of the research findings and outcomes. The main goal of this action plan component will be to determine/formulate the best pollen material for rain enhancement that can be grown within UAE. If required importing the pollen grains may be considered depending on the research outcomes.

Action Plan Component – 2: Growing the seeding material

With the right pollen material determined, selecting the suitable areas for plantation of the pollen generating plants will be the next action plan step. This will be the primary step of this component where in the main focus will be to find existing farms that can accommodate an extra field for the growth of these plants, in order to reduce infrastructural costs and also in consideration would be the physical location of the farm such that it is closest to the point where seeding will take place. The farm size will be determined based on the data obtained in component-1.

The secondary step of the component will be to work with farmers at the plantations to grow the pollen with the right quality and standard. This will also be a learning and building step for future operations of rain enhancement within and outside of UAE, that will be based on natural sources for seeding.

Action Plan Component – 3: Planning and conducting the cloud seeding experiments

The aim of this component will be to plan the cloud seeding experiments with the pollen grains in terms of selecting the right seasons and timings that also match the growth period of the pollen. The idea is to have twice a year experiment during the summer and winter seasons. Therefore proper planning is needed to have sufficient supply of pollen for the experiment and at the right time. The second branch of planning will also be in the practical cloud seeding procedure. Since the material here is different from the conventional material, there needs to be prior planning of the right seeding procedure and a check for the right equipment requirement.

Action Plan Component – 4: Optimizing the cloud seeding process

Cloud seeding process has other alternatives that the conventional method of using airplanes. With pollen it has been also seen that the natural travel of pollen to higher atmospheric levels can also trigger cloud seeding without having the need of artificial transport. However this is influenced by several factors. It would be a great enhancement to the cloud seeding project if the natural transport of pollen is tamed to work in favor of cloud seeding. Therefore based on findings and experiences of the above three components, this component will undertake the work of rationalizing the between natural or artificial cloud seeding processes using pollen.

Action Plan Component – 5: Final implementation

This is the final action step, where all the results from the previous components will be compiled and a final, implantation plan will be made the best, most suitable and least expensive process of rain enhancement through pollen. This plan will further be applied for yearly implementation in UAE.

Who will take these actions?

A consortium of governmental, educational and agricultural bodies will be formed that will be responsible for this project. Each institution will have their work packages and specific timelines. The following describes the institutions and their responsibilities.


Where will these actions be taken?

  1. Local UAE university




a. To conduct review, research and development for finding the best pollen plants, materials, farming techniques and locations.


b. To co-ordinate with the agricultural body for timely plantation and production of pollen material.


c. Responsible throughout all action plan components.


2. UAE Ministry of Climate Change and Environment for plants and areas that can be used in planting.




a. To facilitate authorization requirements for the local university where and when needed.

b. To provide data about the rain enhancement program of the UAE and climatic information as and when needed.


c. To facilitate communication between agricultural bodies and local university for implementing the relevant action plan components.


d. Part leader of the practical cloud seeding implementation experiments, but guided by the local university.


e. Responsible throughout all action plan components.


3. Agricultural body for plantation.




a. Responsible for facilitating pollen plant farming.


b. Providing support through farmland, manpower and equipment for farming.


c. Responsible for action plan component 2 and 4.


4. National Center of Meteorology and Seismology (NCMS) for applying the rain enhancement process.




a. Main leader of the cloud seeding experiments and implementation, guided by local university and UAE environment ministry.


b. Responsible for action plan component 3, 4 and 5.


What are other key benefits?

  1. Reduces the negative effects of the currently used methods of rain enhancement.
  2. Makes use of available natural sources in the process.
  3. Increases the green cover of the country.
  4. Encourages students from local institutes and universities to participate in innovative research on pollen grains as cloud condensation nuclei and rain enhancement.
  5. Instigates farmers to plants new types of plants in the country and be part of the environmental wellbeing of the nation.
  6. Reduces the cost of the process in the long term.

What are the proposal’s costs?

Estimated total cost $ 220,000 (cost of project, with few implementation experiments. Does not include yearly implementation)

Action plan component – 1 - $ 100,000

                  Includes research costs.

Action plan component – 2 - $ 60,000

                  Includes farming contract costs.

Action plan component – 3 - $ 60,000

                  Includes costs for few experiments of cloud seeding process.

Time line

Short term 5 years

  • 2 years of research ( 4 seasons, 2 winters and summers)
  • 1 year planting
  • 2 year applying the cloud seeding

Related proposals

Agroforestry for Water and Energy


  • Pope, F. D. (2010). Pollen grains are efficient cloud condensation nuclei. Environmental Research Letters, 5(4), 044015. doi:10.1088/1748-9326/5/4/044015
  • Steiner, A. L., Brooks, S. D., Deng, C., Thornton, D. C., Pendleton, M. W., & Bryant, V. (2015). Pollen as atmospheric cloud condensation nuclei. Geophysical Research Letters, 42(9), 3596-3602. doi:10.1002/2015gl064060
  • Diehl, K., Quick, C., Matthias-Maser, S., Mitra, S., & Jaenicke, R. (2001). The ice nucleating ability of pollen. Atmospheric Research, 58(2), 75-87. doi:10.1016/s0169-8095(01)00091-6
  • Diehl, K., Matthias-Maser, S., Jaenicke, R., & Mitra, S. (2002). The ice nucleating ability of pollen:. Atmospheric Research, 61(2), 125-133. doi:10.1016/s0169-8095(01)00132-6
  • Mangroves in UAE. (n.d.). Retrieved from